Edition 0
smb.conf Filehttpd httpd.conf /etc/openldap/schema/ Directory/etc/sysconfig/ Directory/etc/sysconfig/arpwatch /etc/sysconfig/authconfig /etc/sysconfig/autofs /etc/sysconfig/clock /etc/sysconfig/desktop /etc/sysconfig/dhcpd /etc/sysconfig/firstboot /etc/sysconfig/i18n /etc/sysconfig/init /etc/sysconfig/ip6tables-config /etc/sysconfig/keyboard /etc/sysconfig/named /etc/sysconfig/network /etc/sysconfig/ntpd /etc/sysconfig/radvd /etc/sysconfig/samba /etc/sysconfig/selinux /etc/sysconfig/sendmail /etc/sysconfig/spamassassin /etc/sysconfig/squid /etc/sysconfig/system-config-users /etc/sysconfig/vncservers /etc/sysconfig/xinetd /etc/sysconfig/ DirectoryMono-spaced Bold
To see the contents of the filemy_next_bestselling_novelin your current working directory, enter thecat my_next_bestselling_novelcommand at the shell prompt and press Enter to execute the command.
Press Enter to execute the command.Press Ctrl+Alt+F1 to switch to the first virtual terminal. Press Ctrl+Alt+F7 to return to your X-Windows session.
mono-spaced bold. For example:
File-related classes includefilesystemfor file systems,filefor files, anddirfor directories. Each class has its own associated set of permissions.
Choose → → from the main menu bar to launch Mouse Preferences. In the Buttons tab, click the Left-handed mouse check box and click to switch the primary mouse button from the left to the right (making the mouse suitable for use in the left hand).To insert a special character into a gedit file, choose → → from the main menu bar. Next, choose → from the Character Map menu bar, type the name of the character in the Search field and click . The character you sought will be highlighted in the Character Table. Double-click this highlighted character to place it in the Text to copy field and then click the button. Now switch back to your document and choose → from the gedit menu bar.
Mono-spaced Bold ItalicProportional Bold Italic
To connect to a remote machine using ssh, typesshat a shell prompt. If the remote machine isusername@domain.nameexample.comand your username on that machine is john, typessh john@example.com.Themount -o remountcommand remounts the named file system. For example, to remount thefile-system/homefile system, the command ismount -o remount /home.To see the version of a currently installed package, use therpm -qcommand. It will return a result as follows:package.package-version-release
Publican is a DocBook publishing system.
mono-spaced roman and presented thus:
books Desktop documentation drafts mss photos stuff svn books_tests Desktop1 downloads images notes scripts svgs
mono-spaced roman but add syntax highlighting as follows:
package org.jboss.book.jca.ex1; import javax.naming.InitialContext; public class ExClient { public static void main(String args[]) throws Exception { InitialContext iniCtx = new InitialContext(); Object ref = iniCtx.lookup("EchoBean"); EchoHome home = (EchoHome) ref; Echo echo = home.create(); System.out.println("Created Echo"); System.out.println("Echo.echo('Hello') = " + echo.echo("Hello")); } }
13.
Table of Contents
yum check-update command to see which installed packages on your system have updates available.
yum to install, update or remove packages on your system. All examples in this chapter assume that you have already obtained superuser privileges by using either the su or sudo command.
~]# yum check-update
Loaded plugins: presto, refresh-packagekit, security
PackageKit.x86_64 0.5.3-0.1.20090915git.fc12 fedora
PackageKit-glib.x86_64 0.5.3-0.1.20090915git.fc12 fedora
PackageKit-yum.x86_64 0.5.3-0.1.20090915git.fc12 fedora
PackageKit-yum-plugin.x86_64 0.5.3-0.1.20090915git.fc12 fedora
glibc.x86_64 2.10.90-22 fedora
glibc-common.x86_64 2.10.90-22 fedora
kernel.x86_64 2.6.31-14.fc12 fedora
kernel-firmware.noarch 2.6.31-14.fc12 fedora
rpm.x86_64 4.7.1-5.fc12 fedora
rpm-libs.x86_64 4.7.1-5.fc12 fedora
rpm-python.x86_64 4.7.1-5.fc12 fedora
yum.noarch 3.2.24-4.fc12 fedora
PackageKit — the name of the package
x86_64 — the CPU architecture the package was built for
0.5.3-0.1.20090915git.fc12 — the version of the updated package to be installed
fedora — the repository in which the updated package is located
yum and rpm packages), as well as their dependencies (such as the kernel-firmware, rpm-libs and rpm-python packages), all using yum.
yum update <package_name>:
~]# yum update glibc
Loaded plugins: presto, refresh-packagekit, security
Setting up Install Process
Resolving Dependencies
--> Running transaction check
--> Processing Dependency: glibc = 2.10.90-21 for package: glibc-common-2.10.90-21.x86_64
---> Package glibc.x86_64 0:2.10.90-22 set to be updated
--> Running transaction check
---> Package glibc-common.x86_64 0:2.10.90-22 set to be updated
--> Finished Dependency Resolution
Dependencies Resolved
======================================================================
Package Arch Version Repository Size
======================================================================
Updating:
glibc x86_64 2.10.90-22 fedora 2.7 M
Updating for dependencies:
glibc-common x86_64 2.10.90-22 fedora 6.0 M
Transaction Summary
======================================================================
Install 0 Package(s)
Upgrade 2 Package(s)
Total download size: 8.7 M
Is this ok [y/N]:
Loaded plugins: presto, refresh-packagekit, security — yum always informs you which Yum plugins are installed and enabled. Here, yum is using the presto, refresh-packagekit and security plugins. Refer to Section 1.4, “Yum Plugins” for general information on Yum plugins, or to Section 1.4.3, “Plugin Descriptions” for descriptions of specific plugins.
kernel.x86_64 — you can download and install new kernels safely with yum.
yum always installs a new kernel in the same sense that RPM installs a new kernel when you use the command rpm -i kernel. Therefore, you do not need to worry about the distinction between installing and upgrading a kernel package when you use yum: it will do the right thing, regardless of whether you are using the yum update or yum install command.
rpm -i kernel command (which installs a new kernel) instead of rpm -u kernel (which replaces the current kernel). Refer to Section 3.2.2, “Installing” for more information on installing/updating kernels with RPM.
yum presents the update information and then prompts you as to whether you want it to perform the update; yum runs interactively by default. If you already know which transactions yum plans to perform, you can use the -y option to automatically answer yes to any questions yum may ask (in which case it runs non-interactively). However, you should always examine which changes yum plans to make to the system so that you can easily troubleshoot any problems that might arise.
cat /var/log/yum.log at the shell prompt. The most recent transactions are listed at the end of the log file.
yum update (without any arguments):
~]# yum update
yum command with a set of highly-useful security-centric commands, subcommands and options. Refer to Section 1.4.3, “security (yum-plugin-security)” for specific information.
yum search <term> [more_terms ] command. yum displays the list of matches for each term:
~]# yum search meld kompare
Loaded plugins: presto, refresh-packagekit, security
=============================== Matched: kompare ===============================
kdesdk.x86_64 : The KDE Software Development Kit (SDK)
komparator.x86_64 : Kompare and merge two folders
================================ Matched: meld =================================
meld.noarch : Visual diff and merge tool
python-meld3.x86_64 : An HTML/XML templating system for Python
yum search is useful for searching for packages you do not know the name of, but for which you know a related term.
yum list and related commands provide information about packages, package groups, and repositories.
* (which expands to match any character multiple times) and ? (which expands to match any one character). Be careful to escape both of these glob characters when passing them as arguments to a yum command. If you do not, the bash shell will interpret the glob expressions as pathname expansions, and potentially pass all files in the current directory that match the globs to yum, which is not what you want. Instead, you want to pass the glob expressions themselves to yum, which you can do by either:
~]# yum list available gimp\*plugin\*
Loaded plugins: presto, refresh-packagekit, security
Available Packages
gimp-fourier-plugin.x86_64 0.3.2-3.fc11 fedora
gimp-lqr-plugin.x86_64 0.6.1-2.fc11 updates
~]# yum list installed "krb?-*"
Loaded plugins: presto, refresh-packagekit, security
Installed Packages
krb5-auth-dialog.x86_64 0.12-2.fc12 @fedora
krb5-libs.x86_64 1.7-8.fc12 @fedora
krb5-workstation.x86_64 1.7-8.fc12 @fedora
yum list <glob_expr> [more_glob_exprs ] — List information on installed and available packages matching all glob expressions.
~]# yum list abrt-addon\* abrt-plugin\*
Loaded plugins: presto, refresh-packagekit, security
Installed Packages
abrt-addon-ccpp.x86_64 0.0.9-2.fc12 @fedora
abrt-addon-kerneloops.x86_64 0.0.9-2.fc12 @fedora
abrt-addon-python.x86_64 0.0.9-2.fc12 @fedora
abrt-plugin-bugzilla.x86_64 0.0.9-2.fc12 @fedora
abrt-plugin-kerneloopsreporter.x86_64 0.0.9-2.fc12 @fedora
abrt-plugin-sqlite3.x86_64 0.0.9-2.fc12 @fedora
Available Packages
abrt-plugin-filetransfer.x86_64 0.0.9-2.fc12 fedora
abrt-plugin-logger.x86_64 0.0.9-2.fc12 fedora
abrt-plugin-mailx.x86_64 0.0.9-2.fc12 fedora
abrt-plugin-runapp.x86_64 0.0.9-2.fc12 fedora
abrt-plugin-sosreport.x86_64 0.0.9-2.fc12 fedora
abrt-plugin-ticketuploader.x86_64 0.0.9-2.fc12 fedora
yum list all — List all installed and available packages.
yum list installed — List all packages installed on your system. The rightmost column in the output lists the repository from which the package was retrieved.
yum list available — List all available packages in all enabled repositories.
yum grouplist — List all package groups.
yum repolist — List the repository ID, name, and number of packages it provides for each enabled repository.
yum info <package_name> [more_names ] displays information about one or more packages (glob expressions are valid here as well):
~]# yum info abrt
Loaded plugins: presto, refresh-packagekit, security
Installed Packages
Name : abrt
Arch : x86_64
Version : 0.0.9
Release : 2.fc12
Size : 525 k
Repo : installed
From repo : fedora
Summary : Automatic bug detection and reporting tool
URL : https://fedorahosted.org/abrt/
License : GPLv2+
Description: abrt is a tool to help users to detect defects in applications and
: to create bug reports that include all information required by the
: maintainer to hopefully resolve it. It uses a plugin system to extend
: its functionality.
yum info <package_name> is similar to the rpm -q --info <package_name> command, but provides as additional information the ID of the Yum repository the RPM package is found in (look for the From repo: line in the output).
yumdb info <package_name> [more_names ] can be used to query the Yum database for alternative and useful information about a package, including the checksum of the package (and algorithm used to produce it, such as SHA-256), the command given on the command line that was invoked to install the package (if any), and the reason that the package is installed on the system (where user indicates it was installed by the user, and dep means it was brought in as a dependency):
~]# yumdb info yum
yum-3.2.27-3.fc12.noarch
checksum_data = 8d7773ec28c954c69c053ea4bf61dec9fdea11a59c50a2c31d1aa2e24bc611d9
checksum_type = sha256
command_line = update
from_repo = updates
from_repo_revision = 1272392716
from_repo_timestamp = 1272414297
reason = user
releasever = 12
man yumdb for more information on the yumdb command.
yum history command, which is new in Fedora 13, can be used to show a timeline of Yum transactions, the dates and times on when they occurred, the number of packages affected, whether transactions succeeded or were aborted, and if the RPM database was changed between transactions. Refer to the history section of man yum for details.
~]# yum install <package_name>
yum install <package_name> [more_names] .
.arch to the package name:
~]# yum install sqlite2.i586
~]# yum install audacious-plugins-\*
yum install. If you know the name of the binary you want to install, but not its package name, you can give yum install the path name:
~]# yum install /usr/sbin/named
yum then searches through its package lists, finds the package which provides /usr/sbin/named, if any, and prompts you as to whether you want to install it.
named binary, but don't know in which bin or sbin directory that file lives? In that situation, you can give yum provides a glob expression:
~]#yum provides "*bin/named"Loaded plugins: presto, refresh-packagekit, security 32:bind-9.6.1-0.3.b1.fc11.x86_64 : The Berkeley Internet Name Domain (BIND) DNS (Domain Name System) server Repo : fedora Matched from: Filename : /usr/sbin/named ~]#yum install bind
yum provides is the same as yum whatprovides.
yum provides "*/<file_name>" is a common and useful trick to quickly find the package(s) that contain <file_name>.
yum grouplist -v command lists the names of all package groups, and, next to each of them, their groupid in parentheses. The groupid is always the term in the last pair of parentheses, such as kde-desktop and kde-software-development in this example:
~]# yum -v grouplist kde\*
KDE (K Desktop Environment) (kde-desktop)
KDE Software Development (kde-software-development)
groupinstall:
~]# yum groupinstall "KDE (K Desktop Environment)"
~]# yum groupinstall kde-desktop
install command if you prepend it with an @-symbol (which tells yum that you want to perform a groupinstall):
~]# yum install @kde-desktop
yum remove <package_name> uninstalls (removes in RPM and Yum terminology) the package, as well as any packages that depend on it. As when you install multiple packages, you can remove several at once by adding more package names to the command:
~]# yum remove foo bar baz
install command, remove can take, as arguments, package names, glob expressions, file lists or package provides.
install syntax.
~]#yum groupremove "KDE (K Desktop Environment)"~]#yum groupremove kde-desktop~]#yum remove @kde-desktop
yum to remove only those packages which are not required by any other packages or groups by adding the groupremove_leaf_only=1 directive to the [main] section of the /etc/yum.conf configuration file. For more information on this directive, refer to Section 1.3.1, “Setting [main] Options”.
[main] section of the /etc/yum.conf configuration file;
repository] sections in /etc/yum.conf and .repo files in the /etc/yum.repos.d/ directory;
/etc/yum.conf and files in /etc/yum.repos.d/so that dynamic version and architecture values are handled correctly; and,
/etc/yum.conf configuration file contains one mandatory [main] section under which you can set Yum options. The values that you define in the [main] section of yum.conf have global effect, and may override values set any individual [repository] sections. You can also add [repository] sections to /etc/yum.conf; however, best practice is to define individual repositories in new or existing .repo files in the /etc/yum.repos.d/directory. Refer to Section 1.3.2, “Setting [repository] Options” if you need to add or edit repository-specific information.
/etc/yum.conf configuration file contains exactly one [main] section. You can add many additional options under the [main] section heading in /etc/yum.conf. Some of the key-value pairs in the [main] section affect how yum operates; others affect how Yum treats repositories. The best source of information for all Yum options is in the [main] OPTIONS and [repository] OPTIONS sections of man yum.conf.
/etc/yum.conf configuration file:
[main]
cachedir=/var/cache/yum/$basearch/$releasever
keepcache=0
debuglevel=2
logfile=/var/log/yum.log
exactarch=1
obsoletes=1
gpgcheck=1
plugins=1
installonly_limit=3
[comments abridged]
# PUT YOUR REPOS HERE OR IN separate files named file.repo
# in /etc/yum.repos.d
[main] section, and descriptions for each:
cachedir=/var/cache/yum/$basearch/$releasever cachedir=/var/cache/yum/$basearch/$releasever . See Section 1.3.3, “Using Yum Variables” for descriptions of the $basearch and $releasever Yum variables.
keepcache=1 instructs yum to keep the cache of headers and packages after a successful installation. keepcache=1 is the default.
.repo files are located. .repo files contain repository information (similar to the [repository] section(s) of /etc/yum.conf). yum collects all repository information from .repo files and the [repository] section of the /etc/yum.conf file to create a master list of repositories to use for transactions. Refer to Section 1.3.2, “Setting [repository] Options” for more information about options you can use for both the [repository] section and .repo files. If reposdir is not set, yum uses the default directory /etc/yum.repos.d/.
gpgcheck=0, which disables GPG-checking. If this option is set in the [main] section of the /etc/yum.conf file, it sets the GPG-checking rule for all repositories. However, you can also set this on individual repositories instead; i.e., you can enable GPG-checking on one repository while disabling it on another. Setting gpgcheck= for individual repositories overrides the default if it is present in /etc/yum.conf. Refer to Section 3.3, “Checking a Package's Signature” for further information on GPG signature-checking.
yum should prompt for confirmation of critical actions. The default is assumeyes=0, which means yum will prompt you for confirmation. If assumeyes=1 is set, yum behaves in the same way that the command line option -y does.
more_names]" * and ?) are allowed.
yum should attempt to retrieve a file before returning an error. Setting this to 0 makes yum retry forever. The default value is 6.
1 causes yum to check the dependencies of each package when removing a package group, and to remove only those packages which are not not required by any other package or group. The default value for this directive is 0, which means that removing a package group will remove all packages in that group regardless of whether they are required by other packages or groups. For more information on removing packages, refer to Smart package group removal.
repository] sections (where repository is a unique repository ID, such as [my_personal_repo]) to /etc/yum.conf or to .repo files in the /etc/yum.repos.d/directory. All .repo files in /etc/yum.repos.d/are read by yum; best practice is to define your repositories here instead of in /etc/yum.conf. You can create new, custom .repo files in this directory, add [repository] sections to those files, and the next time you run a yum command, it will take all newly-added repositories into account.
.repo file should take:
[repository_ID] name=A Repository Name baseurl=http://path/to/repo or ftp://path/to/repo or file://path/to/local/repo
repository] section must contain the following minimum parts:
baseurl=http://path/to/repo/releases/$releasever/server/$basearch/os/
baseurl= line by prepending it as username:password@link. For example, if a repository on http://www.example.com/repo/ requires a username of "user" and a password of "password", then the baseurl link can be specified as baseurl=http://user:password@www.example.com/repo/
repository] options:
enabled=0 instructs yum not to include that repository as a package source when performing updates and installs. This is an easy way of quickly turning repositories on and off, which is useful when you desire a single package from a repository that you do not want to enable for updates, etc. Turning repositories on and off can also be performed quickly by passing either the --enablerepo=<repo_name> or --disablerepo=<repo_name> option to yum, or easily through PackageKit's Add/Remove Software window. For the latter, refer to Section 2.2.1, “Refreshing Software Sources (Yum Repositories)”.
repository] options exist. Refer to the [repository] OPTIONS section of man yum.conf for the exhaustive list.
yum commands and in all Yum configuration files (/etc/yum.conf and all .repo files in /etc/yum.repos.d/.
$releasever $releasever from the distroverpkg=<value> line in the /etc/yum.conf configuration file. If there is no such line in /etc/yum.conf, then yum infers the correct value by deriving the version number from the redhat-release package.
$arch os.uname() function. Valid values for $arch include: i586, i686 and x86_64.
$basearch $basearch to reference the base architecture of the system. For example, i686 and i586 machines both have a base architecture of i386, and AMD64 and Intel64 machines have a base architecture of x86_64.
$YUM0-9 /etc/yum.conf for example) and a shell environment variable with the same name does not exist, then the configuration file variable is not replaced.
createrepo package:
~]# yum install createrepo
/mnt/local_repo/.
createrepo --database command on that directory:
~]# createrepo --database /mnt/local_repo
yum operations.
yum command:
~]# yum info yum
Loaded plugins: presto, refresh-packagekit, security
[output truncated]
Loaded plugins are the names you can provide to the --disableplugins=<plugin_name> option.
plugins= is present in the [main] section of /etc/yum.conf, and that its value is set to 1:
plugins=1
plugins=0.
/etc/yum/pluginconf.d/ directory. You can set plugin-specific options in these files. For example, here is the security plugin's security.conf configuration file:
[main] enabled=1
[main] section (similar to Yum's /etc/yum.conf file) in which there is (or you can place if it is missing) an enabled= option that controls whether the plugin is enabled when you run yum commands.
enabled=0 in /etc/yum.conf, then all plugins are disabled regardless of whether they are enabled in their individual configuration files.
yum command, use the --noplugins option.
yum command, then you can add the --disableplugin=<plugin_name> option to the command:
~]# yum update --disableplugin=presto
--disableplugin= option are the same names listed after the Loaded plugins: line in the output of any yum command. You can disable multiple plugins by separating their names with commas. In addition, you can match multiple similarly-named plugin names or simply shorten long ones by using glob expressions: --disableplugin=presto,refresh-pack*.
yum-plugin-<plugin_name> package-naming convention, but not always: the package which provides the presto plugin is named yum-presto, for example. You can install a Yum plugin in the same way you install other packages:
~]# yum install yum-plugin-security
yum package and all packages it depends on from being purposefully or accidentally removed. This simple scheme prevents many of the most important packages necessary for your system to run from being removed. In addition, you can list more packages, one per line, in the /etc/sysconfig/protected-packages file[1] (which you should create if it does not exist), and protect-packages will extend protection-from-removal to those packages as well. To temporarily override package protection, use the --override-protection option with an applicable yum command.
yum with a set of highly-useful security-related commands, subcommands and options.
~]# yum check-update --security
Loaded plugins: presto, refresh-packagekit, security
Limiting package lists to security relevant ones
Needed 3 of 7 packages, for security
elinks.x86_64 0.12-0.13.pre3.fc11 fedora
kernel.x86_64 2.6.30.8-64.fc11 fedora
kernel-headers.x86_64 2.6.30.8-64.fc11 fedora
yum update --security or yum update-minimal --security to update those packages which are affected by security advisories. Both of these commands update all packages on the system for which a security advisiory has been issued. yum update-minimal --security updates them to the latest packages which were released as part of a security advisory, while yum update --security will update all packages affected by a security advisory to the latest version of that package available.
yum update-minimal --security will update you to kernel-2.6.30.8-32, and yum update --security will update you to kernel-2.6.30.8-64. Conservative system administrators may want to use update-minimal to reduce the risk incurred by updating packages as much as possible.
man yum-security for usage details and further explanation of the enhancements the security plugin adds to yum.
Yum Guides section of the wiki contains more Yum documentation.
[1]
You can also place files with the extension .list in the /etc/sysconfig/protected-packages.d/ directory (which you should create if it does not exist), and list packages—one per line—in these files. protect-packages will protect these too.
gpk-update-viewer command at the shell prompt. In the Software Updates window, all available updates are listed along with the names of the packages being updated (minus the .rpm suffix, but including the CPU architecture), a short summary of the package, and, usually, short descriptions of the changes the update provides. Any updates you do not wish to install can be de-selected here by unchecking the checkbox corresponding to the update.
kernel package, then it will prompt you after installation, asking you whether you want to reboot the system and thereby boot into the newly-installed kernel.
gpk-application command at the shell prompt.
name=<My Repository Name> field of all [repository] sections in the /etc/yum.conf configuration file, and in all repository.repo/etc/yum.repos.d/ directory.
enabled=<1 or 0> field in [repository] sections. Checking an unchecked box enables the Yum repository, and unchecking it disables it. Performing either function causes PolicyKit to prompt for superuser authentication to enable or disable the repository. PackageKit actually inserts the enabled=<1 or 0> line into the correct [repository] section if it does not exist, or changes the value if it does. This means that enabling or disabling a repository through the Software Sources window causes that change to persist after closing the window or rebooting the system. The ability to quickly enable and disable repositories based on our needs is a highly-convenient feature of PackageKit.
<package_name>-devel
<package> <package>-devel
<package>-libs
<package>-libs-devel
<package>-debuginfo
crontabs-1.10-31.fc12.noarch.rpm) are never filtered out by checking . This filter has no affect on non-multilib systems, such as x86 machines.
htop, an colorful and enhanced version of the top process viewer, by opening a shell prompt and entering:
~]$ htop
top is good enough for us and we want to uninstall it. Remembering that we need to change the filter we recently used to install it to in → , we search for htop again and uncheck it. The program did not install any dependencies of its own; if it had, those would be automatically removed as well, as long as they were not also dependencies of any other packages still installed on our system.
gpk-log command at the shell prompt.
Updated System or Installed Packages, the Date on which that action was performed, the Username of the user who performed the action, and the front end Application the user used (such as Update Icon, or kpackagekit). The Details column provides the types of the transactions, such as Updated, Installed or Removed, as well as the list of packages the transactions were performed on.
packagekitd daemon back end, which communicates with a package manager-specific back end that utilizes Yum (on Fedora) to perform the actual transactions, such as installing and removing packages, etc.
| Window Title | Function | How to Open | Shell Command |
|---|---|---|---|
| Add/Remove Software | Install, remove or view package info |
From the GNOME panel: → →
| gpk-application |
| Software Update | Perform package updates |
From the GNOME panel: → →
| gpk-update-viewer |
| Software Sources | Enable and disable Yum repositories |
From Add/Remove Software: →
| gpk-repo |
| Software Log Viewer | View the transaction log |
From Add/Remove Software: →
| gpk-log |
| Software Update Preferences | Set PackageKit preferences | gpk-prefs | |
| (Notification Area Alert) | Alerts you when updates are available |
From the GNOME panel: → → , Application Autostart tab
| gpk-update-icon |
packagekitd daemon runs outside the user session and communicates with the various graphical front ends. The packagekitd daemon[2] communicates via the DBus system message bus with another back end, which utilizes Yum's Python API to perform queries and make changes to the sytem. On Linux systems other than Red Hat and Fedora, packagekitd can communicate with other back ends that are able to utilize the native package manager for that system. This modular architecture provides the abstraction necessary for the graphical interfaces to work with many different package managers to perform essentially the same types of package management tasks. Learning how to use the PackageKit front ends means that you can use the same familiar graphical interface across many different Linux distributions, even when they utilize a native package manager other than Yum.
packagekitd daemon, which runs outside of the user session.
gnome-packagekit package instead of by PackageKit and its dependencies. Users working in a KDE environment may prefer to install the kpackagekit package, which provides a KDE interface for PackageKit.
pkcon.
[2]
System daemons are typically long-running processes that provide services to the user or to other programs, and which are started, often at boot time, by special initialization scripts (often shortened to init scripts). Daemons respond to the service command and can be turned on or off permanently by using the chkconfig on or chkconfig offcommands. They can typically be recognized by a “d ” appended to their name, such as the packagekitd daemon. Refer to Chapter 6, Controlling Access to Services for information about system services.
x86_64.rpm.
.tar.gz files.
rpm --help or man rpm. You can also refer to Section 3.5, “Additional Resources” for more information on RPM.
tree-1.5.2.2-4.fc13.x86_64.rpm. The file name includes the package name (tree), version (1.5.2.2), release (4), operating system major version (fc13) and CPU architecture (x86_64). Assuming the tree-1.5.2.2-4.fc13.x86_64.rpm package is in the current directory, log in as root and type the following command at a shell prompt to install it:
rpm -ivh tree-1.5.2.2-4.fc13.x86_64.rpm
-i option tells rpm to install the package, and the -v and -h options (which are combined with -i) cause rpm to print more verbose output and display a progress meter using hash marks.
-U option, which upgrades the package if an older version is already installed, or simply installs it if not:
rpm -Uvh tree-1.5.2.2-4.fc13.x86_64.rpm
Preparing... ########################################### [100%] 1:tree ########################################### [100%]
error: tree-1.5.2.2-4.fc13.x86_64.rpm: Header V3 RSA/SHA256 signature: BAD, key ID d22e77f2
error: tree-1.5.2.2-4.fc13.x86_64.rpm: Header V3 RSA/SHA256 signature: BAD, key ID d22e77f2
NOKEY:
warning: tree-1.5.2.2-4.fc13.x86_64.rpm: Header V3 RSA/SHA1 signature: NOKEY, key ID 57bbccba
rpm -ivh command (simple install) instead of rpm -Uvh. The reason for this is that install (-i) and upgrade (-U) take on specific meanings when installing kernel packages. Refer to Chapter 28, Manually Upgrading the Kernel for details.
Preparing... ########################################### [100%] package tree-1.5.2.2-4.fc13.x86_64 is already installed
--replacepkgs option, which tells RPM to ignore the error:
rpm -ivh --replacepkgs tree-1.5.2.2-4.fc13.x86_64.rpm
Preparing... ################################################## file /usr/bin/foobar from install of foo-1.0-1.fc13 conflicts with file from package bar-3.1.1.fc13
--replacefiles option:
rpm -ivh --replacefiles foo-1.0-1.fc13.x86_64.rpm
error: Failed dependencies:
bar.so.3()(64bit) is needed by foo-1.0-1.fc13.x86_64
Suggested resolutions:
bar-3.1.1.fc13.x86_64.rpm
rpm -ivh foo-1.0-1.fc13.x86_64.rpm bar-3.1.1.fc13.x86_64.rpm
Preparing... ########################################### [100%] 1:foo ########################################### [ 50%] 2:bar ########################################### [100%]
--whatprovides option to determine which package contains the required file.
rpm -q --whatprovides "bar.so.3"
bar.so.3 is in the RPM database, the name of the package is displayed:
bar-3.1.1.fc13.i586.rpm
rpm to install a package that gives us a Failed dependencies error (using the --nodeps option), this is not recommended, and will usually result in the installed package failing to run. Installing or removing packages with rpm --nodeps can cause applications to misbehave and/or crash, and can cause serious package management problems or, possibly, system failure. For these reasons, it is best to heed such warnings; the package manager—whether RPM, Yum or PackageKit—shows us these warnings and suggests possible fixes because accounting for dependencies is critical. The Yum package manager can perform dependency resolution and fetch dependencies from online repositories, making it safer, easier and smarter than forcing rpm to carry out actions without regard to resolving dependencies.
rpm -e foo
foo, not the name of the original package file, foo-1.0-1.fc13.x86_64. If you attempt to uninstall a package using the rpm -e command and the original full file name, you will receive a package name error.
rpm -e ghostscript
error: Failed dependencies:
libgs.so.8()(64bit) is needed by (installed) libspectre-0.2.2-3.fc13.x86_64
libgs.so.8()(64bit) is needed by (installed) foomatic-4.0.3-1.fc13.x86_64
libijs-0.35.so()(64bit) is needed by (installed) gutenprint-5.2.4-5.fc13.x86_64
ghostscript is needed by (installed) printer-filters-1.1-4.fc13.noarch
<library_name>.so.<number> ~]# rpm -q --whatprovides "libgs.so.8()(64bit)"
ghostscript-8.70-1.fc13.x86_64
rpm to remove a package that gives us a Failed dependencies error (using the --nodeps option), this is not recommended, and may cause harm to other installed applications. Installing or removing packages with rpm --nodeps can cause applications to misbehave and/or crash, and can cause serious package management problems or, possibly, system failure. For these reasons, it is best to heed such warnings; the package manager—whether RPM, Yum or PackageKit—shows us these warnings and suggests possible fixes because accounting for dependencies is critical. The Yum package manager can perform dependency resolution and fetch dependencies from online repositories, making it safer, easier and smarter than forcing rpm to carry out actions without regard to resolving dependencies.
-U option) is similar to installing one (the -i option). If we have the RPM named tree-1.5.3.0-1.fc13.x86_64.rpm in our current directory, and tree-1.5.2.2-4.fc13.x86_64.rpm is already installed on our system (rpm -qi will tell us which version of the tree package we have installed on our system, if any), then the following command will upgrade tree to the newer version:
rpm -Uvh tree-1.5.3.0-1.fc13.x86_64.rpm
foo package. Note that -U will also install a package even when there are no previous versions of the package installed.
-U option for installing kernel packages because RPM completely replaces the previous kernel package. This does not affect a running system, but if the new kernel is unable to boot during your next restart, there would be no other kernel to boot instead.
-i option adds the kernel to your GRUB boot menu (/etc/grub.conf). Similarly, removing an old, unneeded kernel removes the kernel from GRUB.
saving /etc/foo.conf as /etc/foo.conf.rpmsave
foo.conf.rpmnew, and leave the configuration file you modified untouched. You should still resolve any conflicts between your modified configuration file and the new one, usually by merging changes from the old one to the new one with a diff program.
package foo-2.0-1.fc13.x86_64.rpm (which is newer than foo-1.0-1) is already installed
--oldpackage option:
rpm -Uvh --oldpackage foo-1.0-1.fc13.x86_64.rpm
rpm -Fvh foo-2.0-1.fc13.x86_64.rpm
*.rpm glob:
rpm -Fvh *.rpm
/var/lib/rpm/, and is used to query what packages are installed, what versions each package is, and to calculate any changes to any files in the package since installation, among other use cases.
-q option. The rpm -q package name command displays the package name, version, and release number of the installed package <package_name>. For example, using rpm -q tree to query installed package tree might generate the following output:
tree-1.5.2.2-4.fc13.x86_64
man rpm for details) to further refine or qualify your query:
-a — queries all currently installed packages.
-f <file_name> — queries the RPM database for which package owns <file_name> rpm -qf /bin/ls instead of rpm -qf ls).
-p <package_file> — queries the uninstalled package <package_file> -i displays package information including name, description, release, size, build date, install date, vendor, and other miscellaneous information.
-l displays the list of files that the package contains.
-s displays the state of all the files in the package.
-d displays a list of files marked as documentation (man pages, info pages, READMEs, etc.) in the package.
-c displays a list of files marked as configuration files. These are the files you edit after installation to adapt and customize the package to your system (for example, sendmail.cf, passwd, inittab, etc.).
-v to the command to display the lists in a familiar ls -l format.
rpm -V verifies a package. You can use any of the Verify Options listed for querying to specify the packages you wish to verify. A simple use of verifying is rpm -V tree, which verifies that all the files in the tree package are as they were when they were originally installed. For example:
rpm -Vf /usr/bin/tree
/usr/bin/tree is the absolute path to the file used to query a package.
rpm -Va
rpm -Vp tree-1.5.2.2-4.fc13.x86_64.rpm
c" denotes a configuration file) and then the file name. Each of the eight characters denotes the result of a comparison of one attribute of the file to the value of that attribute recorded in the RPM database. A single period (.) means the test passed. The following characters denote specific discrepancies:
5 — MD5 checksum
S — file size
L — symbolic link
T — file modification time
D — device
U — user
G — group
M — mode (includes permissions and file type)
? — unreadable file (file permission errors, for example)
<rpm_file> is the file name of the RPM package):
rpm -K --nosignature <rpm_file>
<rpm_file>: rsa sha1 (md5) pgp md5 OK-K with -Kvv in the command.
x files as well.
/etc/pki/rpm-gpg/ directory. To verify a Fedora Project package, first import the correct key based on your processor architecture:
rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-fedora-x86_64
rpm -qa gpg-pubkey*
gpg-pubkey-57bbccba-4a6f97af
rpm -qi followed by the output from the previous command:
rpm -qi gpg-pubkey-57bbccba-4a6f97af
<rpm_file> with the filename of the RPM package):
rpm -K <rpm_file>
rsa sha1 (md5) pgp md5 OK. This means that the signature of the package has been verified, that it is not corrupt, and is therefore safe to install and use.
rpm -Va
rpm -qf /usr/bin/ghostscript
ghostscript-8.70-1.fc13.x86_64
/usr/bin/paste. You would like to verify the package that owns that program, but you do not know which package owns paste. Enter the following command,
rpm -Vf /usr/bin/paste
rpm -qdf /usr/bin/free
/usr/share/doc/procps-3.2.8/BUGS /usr/share/doc/procps-3.2.8/FAQ /usr/share/doc/procps-3.2.8/NEWS /usr/share/doc/procps-3.2.8/TODO /usr/share/man/man1/free.1.gz /usr/share/man/man1/pgrep.1.gz /usr/share/man/man1/pkill.1.gz /usr/share/man/man1/pmap.1.gz /usr/share/man/man1/ps.1.gz /usr/share/man/man1/pwdx.1.gz /usr/share/man/man1/skill.1.gz /usr/share/man/man1/slabtop.1.gz /usr/share/man/man1/snice.1.gz /usr/share/man/man1/tload.1.gz /usr/share/man/man1/top.1.gz /usr/share/man/man1/uptime.1.gz /usr/share/man/man1/w.1.gz /usr/share/man/man1/watch.1.gz /usr/share/man/man5/sysctl.conf.5.gz /usr/share/man/man8/sysctl.8.gz /usr/share/man/man8/vmstat.8.gz
rpm -qip crontabs-1.10-31.fc13.noarch.rpm
Name : crontabs Relocations: (not relocatable) Version : 1.10 Vendor: Fedora Project Release : 31.fc13 Build Date: Sat 25 Jul 2009 06:37:57 AM CEST Install Date: (not installed) Build Host: x86-6.fedora.phx.redhat.com Group : System Environment/Base Source RPM: crontabs-1.10-31.fc13.src.rpm Size : 2486 License: Public Domain and GPLv2 Signature : RSA/SHA1, Tue 11 Aug 2009 01:11:19 PM CEST, Key ID 9d1cc34857bbccba Packager : Fedora Project Summary : Root crontab files used to schedule the execution of programs Description : The crontabs package contains root crontab files and directories. You will need to install cron daemon to run the jobs from the crontabs. The cron daemon such as cronie or fcron checks the crontab files to see when particular commands are scheduled to be executed. If commands are scheduled, it executes them. Crontabs handles a basic system function, so it should be installed on your system.
crontabs RPM package installs. You would enter the following:
rpm -qlp crontabs-1.10-31.fc13.noarch.rpm
/etc/cron.daily /etc/cron.hourly /etc/cron.monthly /etc/cron.weekly /etc/crontab /usr/bin/run-parts /usr/share/man/man4/crontabs.4.gz
rpm --help — This command displays a quick reference of RPM parameters.
man rpm — The RPM man page gives more detail about RPM parameters than the rpm --help command.
Table of Contents
smb.conf Filehttpd httpd.conf /etc/openldap/schema/ Directory/etc/sysconfig/network-scripts/ directory. The scripts used to activate and deactivate these network interfaces are also located here. Although the number and type of interface files can differ from system to system, there are three categories of files that exist in this directory:
/etc/hosts 127.0.0.1) as localhost.localdomain. For more information, refer to the hosts man page.
/etc/resolv.conf resolv.conf man page.
/etc/sysconfig/network /etc/sysconfig/network ”.
/etc/sysconfig/network-scripts/ifcfg-<interface-name> /etc/sysconfig/networking/ directory is used by the Network Administration Tool (system-config-network) and its contents should not be edited manually. Using only one method for network configuration is strongly encouraged, due to the risk of configuration deletion.
ifcfg-<name> , where <name> refers to the name of the device that the configuration file controls.
ifcfg-eth0, which controls the first Ethernet network interface card or NIC in the system. In a system with multiple NICs, there are multiple ifcfg-eth<X> files (where <X> is a unique number corresponding to a specific interface). Because each device has its own configuration file, an administrator can control how each interface functions individually.
ifcfg-eth0 file for a system using a fixed IP address:
DEVICE=eth0 BOOTPROTO=none ONBOOT=yes NETMASK=255.255.255.0 IPADDR=10.0.1.27 USERCTL=no
ifcfg-eth0 file for an interface using DHCP looks different because IP information is provided by the DHCP server:
DEVICE=eth0 BOOTPROTO=dhcp ONBOOT=yes
system-config-network) is an easy way to make changes to the various network interface configuration files (refer to Chapter 5, Network Configuration for detailed instructions on using this tool).
BONDING_OPTS=<parameters> /etc/sysconfig/network-scripts/ifcfg-bond<N> (see Section 4.2.2, “Channel Bonding Interfaces”). These parameters are identical to those used for bonding devices in /sys/class/net/<bonding device>/bonding, and the module parameters for the bonding driver as described in bonding Module Directives.
BONDING_OPTS in ifcfg-<name> , do not use /etc/modprobe.conf to specify options for the bonding device.
BOOTPROTO=<protocol> <protocol> none — No boot-time protocol should be used.
bootp — The BOOTP protocol should be used.
dhcp — The DHCP protocol should be used.
BROADCAST=<address> <address> ifcalc.
DEVICE=<name> <name> DHCP_HOSTNAME DNS{1,2}=<address> <address> /etc/resolv.conf if the PEERDNS directive is set to yes.
ETHTOOL_OPTS=<options> <options> ethtool. For example, if you wanted to force 100Mb, full duplex:
ETHTOOL_OPTS="autoneg off speed 100 duplex full"
ETHTOOL_OPTS to set the interface speed and duplex settings. Custom initscripts run outside of the network init script lead to unpredictable results during a post-boot network service restart.
autoneg off option. This needs to be stated first, as the option entries are order-dependent.
GATEWAY=<address> <address> is the IP address of the network router or gateway device (if any).
HWADDR=<MAC-address> <MAC-address> is the hardware address of the Ethernet device in the form AA:BB:CC:DD:EE:FF. This directive must be used in machines containing more than one NIC to ensure that the interfaces are assigned the correct device names regardless of the configured load order for each NIC's module. This directive should not be used in conjunction with MACADDR.
IPADDR=<address> <address> MACADDR=<MAC-address> <MAC-address> is the hardware address of the Ethernet device in the form AA:BB:CC:DD:EE:FF. This directive is used to assign a MAC address to an interface, overriding the one assigned to the physical NIC. This directive should not be used in conjunction with HWADDR.
MASTER=<bond-interface> <bond-interface> SLAVE directive.
NETMASK=<mask> <mask> NETWORK=<address> <address> ifcalc.
ONBOOT=<answer> <answer> yes — This device should be activated at boot-time.
no — This device should not be activated at boot-time.
PEERDNS=<answer> <answer> yes — Modify /etc/resolv.conf if the DNS directive is set. If using DHCP, then yes is the default.
no — Do not modify /etc/resolv.conf.
SLAVE=<bond-interface> <bond-interface> yes — This device is controlled by the channel bonding interface specified in the MASTER directive.
no — This device is not controlled by the channel bonding interface specified in the MASTER directive.
MASTER directive.
SRCADDR=<address> <address> USERCTL=<answer> <answer> yes — Non-root users are allowed to control this device.
no — Non-root users are not allowed to control this device.
bonding kernel module and a special network interface called a channel bonding interface. Channel bonding enables two or more network interfaces to act as one, simultaneously increasing the bandwidth and providing redundancy.
/etc/sysconfig/network-scripts/ directory called ifcfg-bond<N> , replacing <N> with the number for the interface, such as 0.
DEVICE= directive must be bond<N> , replacing <N> with the number for the interface.
DEVICE=bond0
IPADDR=192.168.1.1
NETMASK=255.255.255.0
ONBOOT=yes
BOOTPROTO=none
USERCTL=no
BONDING_OPTS="<bonding parameters separated by spaces>"
MASTER= and SLAVE= directives to their configuration files. The configuration files for each of the channel-bonded interfaces can be nearly identical.
eth0 and eth1 may look like the following example:
DEVICE=eth<N>
BOOTPROTO=none
ONBOOT=yes
MASTER=bond0
SLAVE=yes
USERCTL=no
<N> with the numerical value for the interface.
/etc/modprobe.conf:
alias bond<N> bonding
<N> with the number of the interface, such as 0.
BONDING_OPTS="<bonding parameters>" directive in the ifcfg-bond<N> interface file. They should not be placed in /etc/modprobe.conf. For further instructions and advice on configuring the bonding module and to view the list of bonding parameters, refer to Section 29.5.2, “The Channel Bonding Module”.
ifcfg-<if-name>:<alias-value> naming scheme.
ifcfg-eth0:0 file could be configured to specify DEVICE=eth0:0 and a static IP address of 10.0.0.2, serving as an alias of an Ethernet interface already configured to receive its IP information via DHCP in ifcfg-eth0. Under this configuration, eth0 is bound to a dynamic IP address, but the same physical network card can receive requests via the fixed, 10.0.0.2 IP address.
ifcfg-<if-name>-<clone-name> . While an alias file allows multiple addresses for an existing interface, a clone file is used to specify additional options for an interface. For example, a standard DHCP Ethernet interface called eth0, may look similar to this:
DEVICE=eth0 ONBOOT=yes BOOTPROTO=dhcp
USERCTL directive is no if it is not specified, users cannot bring this interface up and down. To give users the ability to control the interface, create a clone by copying ifcfg-eth0 to ifcfg-eth0-user and add the following line to ifcfg-eth0-user:
USERCTL=yes
eth0 interface using the /sbin/ifup eth0-user command because the configuration options from ifcfg-eth0 and ifcfg-eth0-user are combined. While this is a very basic example, this method can be used with a variety of options and interfaces.
ifcfg-ppp<X> <X> is a unique number corresponding to a specific interface.
wvdial, the Network Administration Tool or Kppp is used to create a dialup account. It is also possible to create and edit this file manually.
ifcfg-ppp0 file:
DEVICE=ppp0 NAME=test WVDIALSECT=test MODEMPORT=/dev/modem LINESPEED=115200 PAPNAME=test USERCTL=true ONBOOT=no PERSIST=no DEFROUTE=yes PEERDNS=yes DEMAND=no IDLETIMEOUT=600
ifcfg-sl0.
DEFROUTE=<answer> <answer> yes — Set this interface as the default route.
no — Do not set this interface as the default route.
DEMAND=<answer> <answer> yes — This interface allows pppd to initiate a connection when someone attempts to use it.
no — A connection must be manually established for this interface.
IDLETIMEOUT=<value> <value> INITSTRING=<string> <string> LINESPEED=<value> <value> 57600, 38400, 19200, and 9600.
MODEMPORT=<device> <device> MTU=<value> <value> 576 results in fewer packets dropped and a slight improvement to the throughput for a connection.
NAME=<name> <name> PAPNAME=<name> <name> PERSIST=<answer> <answer> yes — This interface should be kept active at all times, even if deactivated after a modem hang up.
no — This interface should not be kept active at all times.
REMIP=<address> <address> WVDIALSECT=<name> <name> /etc/wvdial.conf. This file contains the phone number to be dialed and other important information for the interface.
ifcfg-lo /etc/sysconfig/network-scripts/ifcfg-lo, should never be edited manually. Doing so can prevent the system from operating correctly.
ifcfg-irlan0 ifcfg-plip0 /etc/sysconfig/network-scripts/ directory: /sbin/ifdown and /sbin/ifup.
ifup and ifdown interface scripts are symbolic links to scripts in the /sbin/ directory. When either of these scripts are called, they require the value of the interface to be specified, such as:
ifup eth0
ifup and ifdown interface scripts are the only scripts that the user should use to bring up and take down network interfaces.
/etc/rc.d/init.d/functions and /etc/sysconfig/network-scripts/network-functions. Refer to Section 4.5, “Network Function Files” for more information.
/etc/sysconfig/network-scripts/ directory:
ifup-aliases ifup-ippp and ifdown-ippp ifup-ipv6 and ifdown-ipv6 ifup-plip ifup-plusb ifup-post and ifdown-post ifup-ppp and ifdown-ppp ifup-routes ifdown-sit and ifup-sit ifup-wireless /etc/sysconfig/network-scripts/ directory can cause interface connections to act irregularly or fail. Only advanced users should modify scripts related to a network interface.
/sbin/service command on the network service (/etc/rc.d/init.d/network), as illustrated the following command:
/sbin/service network <action>
<action> can be either start, stop, or restart.
/sbin/service network status
route command to display the IP routing table.
/etc/sysconfig/network-scripts/route-interface file. For example, static routes for the eth0 interface would be stored in the /etc/sysconfig/network-scripts/route-eth0 file. The route-interface file has two formats: IP command arguments and network/netmask directives.
defaultX.X.X.Xdevinterface
X.X.X.X is the IP address of the default gateway. The interface is the interface that is connected to, or can reach, the default gateway.
X.X.X.X/XviaX.X.X.Xdevinterface
X.X.X.X/X is the network number and netmask for the static route. X.X.X.X and interface are the IP address and interface for the default gateway respectively. The X.X.X.X address does not have to be the default gateway IP address. In most cases, X.X.X.X will be an IP address in a different subnet, and interface will be the interface that is connected to, or can reach, that subnet. Add as many static routes as required.
route-eth0 file using the IP command arguments format. The default gateway is 192.168.0.1, interface eth0. The two static routes are for the 10.10.10.0/24 and 172.16.1.0/24 networks:
default 192.168.0.1 dev eth0 10.10.10.0/24 via 192.168.0.1 dev eth0 172.16.1.0/24 via 192.168.0.1 dev eth0
10.10.10.0/24 via 10.10.10.1 dev eth1
ifup command: "RTNETLINK answers: File exists" or 'Error: either "to" is a duplicate, or "X.X.X.X" is a garbage.', where X.X.X.X is the gateway, or a different IP address. These errors can also occur if you have another route to another network using the default gateway. Both of these errors are safe to ignore.
route-interface files. The following is a template for the network/netmask format, with instructions following afterwards:
ADDRESS0=X.X.X.XNETMASK0=X.X.X.XGATEWAY0=X.X.X.X
ADDRESS0=X.X.X.X is the network number for the static route.
NETMASK0=X.X.X.X is the netmask for the network number defined with ADDRESS0=X.X.X.X .
GATEWAY0=X.X.X.X is the default gateway, or an IP address that can be used to reach ADDRESS0=X.X.X.X
route-eth0 file using the network/netmask directives format. The default gateway is 192.168.0.1, interface eth0. The two static routes are for the 10.10.10.0/24 and 172.16.1.0/24 networks. However, as mentioned before, this example is not necessary as the 10.10.10.0/24 and 172.16.1.0/24 networks would use the default gateway anyway:
ADDRESS0=10.10.10.0 NETMASK0=255.255.255.0 GATEWAY0=192.168.0.1 ADDRESS1=172.16.1.0 NETMASK1=255.255.255.0 GATEWAY1=192.168.0.1
ADDRESS0, ADDRESS1, ADDRESS2, and so on.
ADDRESS0=10.10.10.0 NETMASK0=255.255.255.0 GATEWAY0=10.10.10.1
/etc/sysconfig/network-scripts/network-functions file contains the most commonly used IPv4 functions, which are useful to many interface control scripts. These functions include contacting running programs that have requested information about changes in the status of an interface, setting hostnames, finding a gateway device, verifying whether or not a particular device is down, and adding a default route.
/etc/sysconfig/network-scripts/network-functions-ipv6 file exists specifically to hold this information. The functions in this file configure and delete static IPv6 routes, create and remove tunnels, add and remove IPv6 addresses to an interface, and test for the existence of an IPv6 address on an interface.
/usr/share/doc/initscripts-<version>/sysconfig.txt /usr/share/doc/iproute-<version>/ip-cref.ps ip command, which can be used to manipulate routing tables, among other things. Use the ggv or kghostview application to view this file.
DSL and PPPoE (Point-to-Point over Ethernet). In addition, NetworkManager allows for the configuration of network aliases, static routes, DNS information and VPN connections, as well as many connection-specific parameters. Finally, NetworkManager provides a rich API via D-Bus which allows applications to query and control network configuration and state.
system-config-network after its command line invocation. In Fedora 13, NetworkManager replaces the former Network Administration Tool while providing enhanced functionality, such as user-specific and mobile broadband configuration. It is also possible to configure the network in Fedora 13 by editing interface configuration files; refer to Chapter 4, Network Interfaces for more information.
~]# yum install NetworkManager
~]# service NetworkManager status
NetworkManager (pid 1527) is running...
service command will report NetworkManager is stopped if the NetworkManager service is not running. To start it for the current session:
~]# service NetworkManager start
chkconfig command to ensure that NetworkManager starts up every time the system boots:
~]# chkconfig NetworkManager on
~]$ nm-applet &
~]$ nm-connection-editor &
/etc/sysconfig/networking/ directory (mainly in ifcfg-<network_type> interface configuration files), user connection settings are stored in GConf and the GNOME keyring, and are available only during login sessions for the user who created them. Thus, logging out of the desktop session causes user-specific connections to become unavailable. Because of this property, users may wish to configure VPN connections as user connections for security purposes.
/etc/sysconfig/networking/ directory, and to delete the GConf settings from the user's session. Conversely, converting a system to a user-specific connection causes NetworkManager to remove the system-wide configuration files and create the corresponding GConf/GNOME keyring settings.
connection_name window and clicking Apply will make it a sysem connection. Unchecking that checkbox will make it a user connection. Depending on the aforementioned policy setting, NetworkManager may invoke PolicyKit to ensure you have the appropriate privileges, in which case you will be prompted for the root password.
| Wired | Wireless | Mobile Broadband | VPN | DSL | |
|---|---|---|---|---|---|
| Wired | Section 5.4.1, “Configuring the Wired Tab” | ||||
| 802.1x Security | Section 5.4.2, “Configuring the 802.1x Security Tab” | ||||
| Wireless | Section 5.4.3, “Configuring the Wireless Tab” | ||||
| Wireless Security | Section 5.4.4, “Configuring the Wireless Security Tab” | ||||
| Mobile Broadband | Section 5.4.5, “Configuring the Mobile Broadband Tab” | ||||
| PPP Settings | Section 5.4.6, “Configuring the PPP Settings Tab” | ||||
| VPN | Section 5.4.7, “Configuring the VPN Tab” | ||||
| DSL | Section 5.4.8, “Configuring the DSL Tab” | ||||
| IPv4 Settings | Section 5.4.9, “Configuring the IPv4 Settings Tab” | ||||
| IPv6 Settings | Section 5.4.10, “Configuring the IPv6 Settings Tab” | ||||
ifconfig command will show the MAC address associated with each interface: HWaddr 00:1C:25:14:4A:E0 for example.
1500 when using IPv4, or a variable number 1280 or higher for IPv6, and does not generally need to be specified or changed.
httpd if you are running a Web server). However, if you do not need to provide a service, you should turn it off to minimize your exposure to possible bug exploits.
xinetd and the services in the /etc/rc.d/init.d hierarchy (also known as SysV services) can be configured to start or stop using three different applications:
xinetd services can not be started, stopped, or restarted using this program.
chkconfig xinetd services can not be started, stopped, or restarted using this utility.
/etc/rc.d by hand or editing the xinetd configuration files in /etc/xinetd.d.
iptables to configure an IP firewall. If you are a new Linux user, note that iptables may not be the best solution for you. Setting up iptables can be complicated, and is best tackled by experienced Linux system administrators.
iptables is flexibility. For example, if you need a customized solution which provides certain hosts access to certain services, iptables can provide it for you. Refer to and for more information about iptables.
/etc/rc.d/rc<x>.d, where <x> is the number of the runlevel.
/etc/inittab file, which contains a line near the top of the file similar to the following:
id:5:initdefault:
xinetd (as well as any program with built-in support for libwrap) can use TCP wrappers to manage access. xinetd can use the /etc/hosts.allow and /etc/hosts.deny files to configure access to system services. As the names imply, hosts.allow contains a list of rules that allow clients to access the network services controlled by xinetd, and hosts.deny contains rules to deny access. The hosts.allow file takes precedence over the hosts.deny file. Permissions to grant or deny access can be based on individual IP address (or hostnames) or on a pattern of clients. Refer to hosts_access in section 5 of the man pages (man 5 hosts_access) for details.
xinetd xinetd, which is a secure replacement for inetd. The xinetd daemon conserves system resources, provides access control and logging, and can be used to start special-purpose servers. xinetd can also be used to grant or deny access to particular hosts, provide service access at specific times, limit the rate of incoming connections, limit the load created by connections, and more.
xinetd runs constantly and listens on all ports for the services it manages. When a connection request arrives for one of its managed services, xinetd starts up the appropriate server for that service.
xinetd is /etc/xinetd.conf, but the file only contains a few defaults and an instruction to include the /etc/xinetd.d directory. To enable or disable an xinetd service, edit its configuration file in the /etc/xinetd.d directory. If the disable attribute is set to yes, the service is disabled. If the disable attribute is set to no, the service is enabled. You can edit any of the xinetd configuration files or change its enabled status using the Services Configuration Tool, ntsysv, or chkconfig. For a list of network services controlled by xinetd, review the contents of the /etc/xinetd.d directory with the command ls /etc/xinetd.d.
/etc/rc.d/init.d directory are started at boot time (for runlevels 3, 4, and 5) and which xinetd services are enabled. It also allows you to start, stop, and restart SysV services as well as reload xinetd.
system-config-services at a shell prompt (for example, in an XTerm or a GNOME terminal).
/etc/rc.d/init.d directory as well as the services controlled by xinetd. Click on the name of the service from the list on the left-hand side of the application to display a brief description of that service as well as the status of the service. If the service is not an xinetd service, the status window shows whether the service is currently running. If the service is controlled by xinetd, the status window displays the phrase xinetd service.
xinetd service, the action buttons are disabled because they cannot be started or stopped individually.
xinetd service by checking or unchecking the checkbox next to the service name, you must select > from the pulldown menu (or the button above the tabs) to reload xinetd and immediately enable/disable the xinetd service that you changed. xinetd is also configured to remember the setting. You can enable/disable multiple xinetd services at a time and save the changes when you are finished.
rsync to enable it in runlevel 3 and then save the changes. The rsync service is immediately enabled. The next time xinetd is started, rsync is still enabled.
xinetd services, xinetd is reloaded, and the changes take place immediately. When you save changes to other services, the runlevel is reconfigured, but the changes do not take effect immediately.
xinetd service to start at boot time for the currently selected runlevel, check the box beside the name of the service in the list. After configuring the runlevel, apply the changes by selecting > from the pulldown menu. The runlevel configuration is changed, but the runlevel is not restarted; thus, the changes do not take place immediately.
httpd service from checked to unchecked and then select , the runlevel 3 configuration changes so that httpd is not started at boot time. However, runlevel 3 is not reinitialized, so httpd is still running. Select one of following options at this point:
httpd service — Stop the service by selecting it from the list and clicking the button. A message appears stating that the service was stopped successfully.
telinit x (where x is the runlevel number; in this example, 3.). This option is recommended if you change the Start at Boot value of multiple services and want to activate the changes immediately.
httpd service. You can wait until the system is rebooted for the service to stop. The next time the system is booted, the runlevel is initialized without the httpd service running.
xinetd-managed service on or off. You can also use ntsysv to configure runlevels. By default, only the current runlevel is configured. To configure a different runlevel, specify one or more runlevels with the --level option. For example, the command ntsysv --level 345 configures runlevels 3, 4, and 5.
xinetd are immediately affected by ntsysv. For all other services, changes do not take effect immediately. You must stop or start the individual service with the command service <daemon> stop (where <daemon> is the name of the service you want to stop; for example, httpd). Replace stop with start or restart to start or restart the service.
chkconfig chkconfig command can also be used to activate and deactivate services. The chkconfig --list command displays a list of system services and whether they are started (on) or stopped (off) in runlevels 0-6. At the end of the list is a section for the services managed by xinetd.
chkconfig --list command is used to query a service managed by xinetd, it displays whether the xinetd service is enabled (on) or disabled (off). For example, the command chkconfig --list rsync returns the following output:
rsync on
rsync is enabled as an xinetd service. If xinetd is running, rsync is enabled.
chkconfig --list to query a service in /etc/rc.d, that service's settings for each runlevel are displayed. For example, the command chkconfig --list httpd returns the following output:
httpd 0:off 1:off 2:on 3:on 4:on 5:on 6:off
chkconfig can also be used to configure a service to be started (or not) in a specific runlevel. For example, to turn nscd off in runlevels 3, 4, and 5, use the following command:
chkconfig --level 345 nscd off
xinetd are immediately affected by chkconfig. For example, if xinetd is running while rsync is disabled, and the command chkconfig rsync on is executed, then rsync is immediately enabled without having to restart xinetd manually. Changes for other services do not take effect immediately after using chkconfig. You must stop or start the individual service with the command service <daemon> stop (where <daemon> is the name of the service you want to stop; for example, httpd). Replace stop with start or restart to start or restart the service.
ntsysv, chkconfig, xinetd, and xinetd.conf.
man 5 hosts_access — The man page for the format of host access control files (in section 5 of the man pages).
xinetd webpage. It contains sample configuration files and a more detailed list of features.
named in Fedora. You can manage it via the Services Configuration Tool (system-config-service).
bob.sales.example.com
. ”). In this example, therefore, com defines the top-level domain for this resource record. The name example is a sub-domain under com, while sales is a sub-domain under example. The name furthest to the left, bob, identifies a resource record which is part of the sales.example.com domain.
bob), each section is called a zone. Zone defines a specific namespace. A zone contains definitions of resource records, which usually contain host-to-IP address mappings and IP address-to-host mappings, which are called reverse records).
/usr/sbin/named, an administration utility called /usr/sbin/rndc and DNS debugging utility called /usr/bin/dig. More information about rndc can be found in Section 7.4, “Using rndc ”.
/etc/named.conf named daemon
/var/named/ directorynamed working directory which stores zone and statistic files
bind-chroot package, the BIND service will run in the /var/named/chroot environment. All configuration files will be moved there. As such, named.conf will be located in /var/named/chroot/etc/named.conf, and so on.
/etc/named.conf named.conf file is a collection of statements using nested options surrounded by opening and closing ellipse characters, { }. Administrators must be careful when editing named.conf to avoid syntax errors as many seemingly minor errors prevent the named service from starting.
named.conf file is organized similar to the following example:
<statement-1>["<statement-1-name>"] [<statement-1-class>] {<option-1>;<option-2>;<option-N>; };<statement-2>["<statement-2-name>"] [<statement-2-class>] {<option-1>;<option-2>;<option-N>; };<statement-N>["<statement-N-name>"] [<statement-N-class>] {<option-1>;<option-2>;<option-N>; };
/etc/named.conf:
acl Statementacl (Access Control List) statement defines groups of hosts which can then be permitted or denied access to the nameserver.
acl statement takes the following form:
acl<acl-name>{<match-element>; [<match-element>; ...] };
<acl-name> with the name of the access control list and replace <match-element> with a semi-colon separated list of IP addresses. Most of the time, an individual IP address or CIDR network notation (such as 10.0.1.0/24) is used to identify the IP addresses within the acl statement.
any — Matches every IP address
localhost — Matches any IP address in use by the local system
localnets — Matches any IP address on any network to which the local system is connected
none — Matches no IP addresses
options statement), acl statements can be very useful in preventing the misuse of a BIND nameserver.
options statement to define how they are treated by the nameserver:
acl black-hats {
10.0.2.0/24; 192.168.0.0/24; 1234:5678::9abc/24;};
acl red-hats { 10.0.1.0/24; };
options {
blackhole { black-hats; };
allow-query { red-hats; };
allow-query-cache { red-hats; };
}
black-hats and red-hats. Hosts in the black-hats list are denied access to the nameserver, while hosts in the red-hats list are given normal access.
include Statementinclude statement allows files to be included in a named.conf file. In this way, sensitive configuration data (such as keys) can be placed in a separate file with restrictive permissions.
include statement takes the following form:
include "<file-name>"
<file-name> is replaced with an absolute path to a file.
options Statementoptions statement defines global server configuration options and sets defaults for other statements. It can be used to specify the location of the named working directory, the types of queries allowed, and much more.
options statement takes the following form:
options {
<option>;
[<option>; ...]
};
<option> directives are replaced with a valid option.
allow-query allow-query-cache allow-query, this option applies to non-authoritative data, like recursive queries. By default, only localhost; and localnets; are allowed to obtain non-authoritative data.
blackhole none;
directory named working directory if different from the default value, /var/named/.
forwarders forward forwarders directive.
first — Specifies that the nameservers listed in the forwarders directive be queried before named attempts to resolve the name itself.
only — Specifies that named does not attempt name resolution itself in the event that queries to nameservers specified in the forwarders directive fail.
listen-on named listens for queries. By default, all IPv4 interfaces are used.
listen-on directive:
options { listen-on { 10.0.1.1; }; };
10.0.1.1) address.
listen-on-v6 listen-on except for IPv6 interfaces.
listen-on-v6 directive:
options { listen-on-v6 { 1234:5678::9abc; }; };
1234:5678::9abc) address.
max-cache-size options { max-cache-size 256M; };
notify named notifies the slave servers when a zone is updated. It accepts the following options:
yes — Notifies slave servers.
no — Does not notify slave servers.
master-only - Send notify only when server is a master server for the zone.
explicit — Only notifies slave servers specified in an also-notify list within a zone statement.
pid-file named.
recursion named acts as a recursive server. The default is yes.
options { recursion no; };
statistics-file named statistics are saved to the /var/named/named.stats file.
named.conf man page for more details.
zone Statementzone statement defines the characteristics of a zone, such as the location of its configuration file and zone-specific options. This statement can be used to override the global options statements.
zone statement takes the following form:
zone<zone-name><zone-class><zone-options>; [<zone-options>; ...] };
<zone-name> is the name of the zone, <zone-class> is the optional class of the zone, and <zone-options> is a list of options characterizing the zone.
<zone-name> attribute for the zone statement is particularly important. It is the default value assigned for the $ORIGIN directive used within the corresponding zone file located in the /var/named/ directory. The named daemon appends the name of the zone to any non-fully qualified domain name listed in the zone file.
zone statement defines the namespace for example.com, use example.com as the <zone-name> so it is placed at the end of hostnames within the example.com zone file.
zone statement options include the following:
allow-query allow-query option. The default is to allow all query requests.
allow-transfer allow-update file named working directory that contains the zone's configuration data.
masters type slave.
notify named notifies the slave servers when a zone is updated. This option has same parameters as a global notify parameter.
type delegation-only — Enforces the delegation status of infrastructure zones such as COM, NET, or ORG. Any answer that is received without an explicit or implicit delegation is treated as NXDOMAIN. This option is only applicable in TLDs or root zone files used in recursive or caching implementations.
forward — Forwards all requests for information about this zone to other nameservers.
hint — A special type of zone used to point to the root nameservers which resolve queries when a zone is not otherwise known. No configuration beyond the default is necessary with a hint zone.
master — Designates the nameserver as authoritative for this zone. A zone should be set as the master if the zone's configuration files reside on the system.
slave — Designates the nameserver as a slave server for this zone. Master server is specified in masters directive.
zone Statements/etc/named.conf file of a master or slave nameserver involves adding, modifying, or deleting zone statements. While these zone statements can contain many options, most nameservers require only a small subset to function efficiently. The following zone statements are very basic examples illustrating a master-slave nameserver relationship.
zone statement for the primary nameserver hosting example.com (192.168.0.1):
zone "example.com" IN {
type master;
file "example.com.zone";
allow-transfer { 192.168.0.2; };
};
example.com, the type is set to master, and the named service is instructed to read the /var/named/example.com.zone file. It also allows only slave nameserver (192.168.0.2) to transfer the zone.
zone statement for example.com is slightly different from the previous example. For a slave server, the type is set to slave and the masters directive is telling named the IP address of the master server.
zone statement for example.com zone:
zone "example.com"{
type slave;
file "slaves/example.com.zone";
masters { 192.168.0.1; };
};
zone statement configures named on the slave server to query the master server at the 192.168.0.1 IP address for information about the example.com zone. The information that the slave server receives from the master server is saved to the /var/named/slaves/example.com.zone file. Make sure you put all slave zones to /var/named/slaves directory otherwise named will fail to transfer the zone.
named.conf:
controls rndc command to administer the named service.
/etc/named.conf ” to learn more about how the controls statement is structured and what options are available.
key "<key-name>" rndc command. Two options are used with key:
algorithm <algorithm-name> — The type of algorithm used, such as hmac-md5.
secret "<key-value>" — The encrypted key.
/etc/rndc.conf ” for instructions on how to write a key statement.
logging channel option within the logging statement, a customized type of log can be constructed — with its own file name (file), size limit (size), versioning (version), and level of importance (severity). Once a customized channel is defined, a category option is used to categorize the channel and begin logging when named is restarted.
named logs standard messages to the syslog daemon, which places them in /var/log/messages. This occurs because several standard channels are built into BIND with various severity levels, such as default_syslog (which handles informational logging messages) and default_debug (which specifically handles debugging messages). A default category, called default, uses the built-in channels to do normal logging without any special configuration.
server named should respond to remote nameservers, especially with regard to notifications and zone transfers.
transfer-format option controls whether one resource record is sent with each message (one-answer) or multiple resource records are sent with each message (many-answers). While many-answers is more efficient, only newer BIND nameservers understand it.
trusted-keys view "<view-name>" match-clients option specifies the IP addresses that apply to a particular view. Any options statement may also be used within a view, overriding the global options already configured for named. Most view statements contain multiple zone statements that apply to the match-clients list. The order in which view statements are listed is important, as the first view statement that matches a particular client's IP address is used.
view statement.
named.conf:
// — When placed at the beginning of a line, that line is ignored by named.
# — When placed at the beginning of a line, that line is ignored by named.
/* and */ — When text is enclosed in these tags, the block of text is ignored by named.
named working directory (/var/named/) by default. Each zone file is named according to the file option data in the zone statement, usually in a way that relates to the domain in question and identifies the file as containing zone data, such as example.com.zone.
bind-chroot package, the BIND service will run in the /var/named/chroot environment. All configuration files will be moved there. As such, you can find the zone files in /var/named/chroot/var/named.
;) in zone files.
$) followed by the name of the directive. They usually appear at the top of the zone file.
$INCLUDE named to include another zone file in this zone file at the place where the directive appears. This allows additional zone settings to be stored apart from the main zone file.
$ORIGIN $ORIGIN example.com.
.) are appended with example.com.
$ORIGIN directive is unnecessary if the zone is specified in /etc/named.conf because the zone name is used as the value for the $ORIGIN directive by default.
$TTL A
<host> IN A <IP-address>
<host> value is omitted, then an A record points to a default IP address for the top of the namespace. This system is the target for all non-FQDN requests.
A record examples for the example.com zone file:
server1 IN A 10.0.1.3 IN A 10.0.1.5
example.com are pointed to 10.0.1.3 or 10.0.1.5.
CNAME named that any requests sent to the <alias-name> should point to the host, <real-name>. CNAME records are most commonly used to point to services that use a common naming scheme, such as www for Web servers.
<alias-name> IN CNAME <real-name>
A record binds a hostname to an IP address, while a CNAME record points the commonly used www hostname to it.
server1 IN A 10.0.1.5 www IN CNAME server1
MX IN MX<preference-value><email-server-name>
<preference-value> allows numerical ranking of the email servers for a namespace, giving preference to some email systems over others. The MX resource record with the lowest <preference-value> is preferred over the others. However, multiple email servers can possess the same value to distribute email traffic evenly among them.
<email-server-name> may be a hostname or FQDN.
IN MX 10 mail.example.com. IN MX 20 mail2.example.com.
mail.example.com email server is preferred to the mail2.example.com email server when receiving email destined for the example.com domain.
NS NS record:
IN NS <nameserver-name>
<nameserver-name> should be an FQDN.
IN NS dns1.example.com. IN NS dns2.example.com.
PTR PTR records are primarily used for reverse name resolution, as they point IP addresses back to a particular name. Refer to Section 7.3.4, “Reverse Name Resolution Zone Files” for more examples of PTR records in use.
SOA SOA resource record is the first resource record in a zone file.
SOA resource record:
@ IN SOA<primary-name-server><hostmaster-email>(<serial-number><time-to-refresh><time-to-retry><time-to-expire><minimum-TTL>)
@ symbol places the $ORIGIN directive (or the zone's name, if the $ORIGIN directive is not set) as the namespace being defined by this SOA resource record. The hostname of the primary nameserver that is authoritative for this domain is the <primary-name-server> directive, and the email of the person to contact about this namespace is the <hostmaster-email> directive.
<serial-number> directive is a numerical value incremented every time the zone file is altered to indicate it is time for named to reload the zone. The <time-to-refresh> directive is the numerical value slave servers use to determine how long to wait before asking the master nameserver if any changes have been made to the zone. The <serial-number> directive is a numerical value used by the slave servers to determine if it is using outdated zone data and should therefore refresh it.
<time-to-retry> directive is a numerical value used by slave servers to determine the length of time to wait before issuing a refresh request in the event that the master nameserver is not answering. If the master has not replied to a refresh request before the amount of time specified in the <time-to-expire> directive elapses, the slave servers stop responding as an authority for requests concerning that namespace.
<minimum-TTL> directive is the amount of time other nameservers cache the zone's information. However, in BIND 9, the <minimum-TTL> directive defines how long negative answers are cached for. Caching of negative answers can be set to a maximum of 3 hours (3H).
M), hours (H), days (D), and weeks (W). The table in Table 7.1, “Seconds compared to other time units” shows an amount of time in seconds and the equivalent time in another format.
| Seconds | Other Time Units |
|---|---|
60
|
1M
|
1800
|
30M
|
3600
|
1H
|
10800
|
3H
|
21600
|
6H
|
43200
|
12H
|
86400
|
1D
|
259200
|
3D
|
604800
|
1W
|
31536000
|
365D
|
SOA resource record might take when it is populated with real values.
@ IN SOA dns1.example.com. hostmaster.example.com. ( 2001062501 ; serial 21600 ; refresh after 6 hours 3600 ; retry after 1 hour 604800 ; expire after 1 week 86400 ) ; minimum TTL of 1 day
$ORIGIN example.com. $TTL 86400 @ SOA dns1.example.com. hostmaster.example.com. ( 2001062501 ; serial 21600 ; refresh after 6 hours 3600 ; retry after 1 hour 604800 ; expire after 1 week 86400 ) ; minimum TTL of 1 day ; ; NS dns1.example.com. NS dns2.example.com. dns1 A 10.0.1.1 AAAA aaaa:bbbb::1 dns2 A 10.0.1.2 AAAA aaaa:bbbb::2 ; ; @ MX 10 mail.example.com. MX 20 mail2.example.com. mail A 10.0.1.5 AAAA aaaa:bbbb::5 mail2 A 10.0.1.6 AAAA aaaa:bbbb::6 ; ; ; This sample zone file illustrates sharing the same IP addresses for multiple services: ; services A 10.0.1.10 AAAA aaaa:bbbb::10 A 10.0.1.11 AAAA aaaa:bbbb::11 ftp CNAME services.example.com. www CNAME services.example.com. ; ;
SOA values are used. The authoritative nameservers are set as dns1.example.com and dns2.example.com, which have A records that tie them to 10.0.1.1 and 10.0.1.2, respectively.
MX records point to mail and mail2 via A records. Since the mail and mail2 names do not end in a trailing period (.), the $ORIGIN domain is placed after them, expanding them to mail.example.com and mail2.example.com. Through the related A resource records, their IP addresses can be determined.
www.example.com (WWW), are pointed at the appropriate servers using a CNAME record.
zone statement in the named.conf similar to the following:
zone "example.com" IN {
type master;
file "example.com.zone";
allow-update { none; };
};
PTR resource records are used to link the IP addresses to a fully qualified domain name.
PTR record:
<last-IP-digit> IN PTR <FQDN-of-system>
<last-IP-digit> is the last number in an IP address which points to a particular system's FQDN.
10.0.1.1 through 10.0.1.6 are pointed to corresponding FQDNs. It can be located in /var/named/example.com.rr.zone.
$ORIGIN 1.0.10.in-addr.arpa. $TTL 86400 @ IN SOA dns1.example.com. hostmaster.example.com. ( 2001062501 ; serial 21600 ; refresh after 6 hours 3600 ; retry after 1 hour 604800 ; expire after 1 week 86400 ) ; minimum TTL of 1 day ; @ IN NS dns1.example.com. ; 1 IN PTR dns1.example.com. 2 IN PTR dns2.example.com. ; 5 IN PTR server1.example.com. 6 IN PTR server2.example.com. ; 3 IN PTR ftp.example.com. 4 IN PTR ftp.example.com.
zone statement in the named.conf file similar to the following:
zone "1.0.10.in-addr.arpa" IN {
type master;
file "example.com.rr.zone";
allow-update { none; };
};
zone statement, except for the zone name. Note that a reverse name resolution zone requires the first three blocks of the IP address reversed followed by .in-addr.arpa. This allows the single block of IP numbers used in the reverse name resolution zone file to be associated with the zone.
rndc rndc which allows command line administration of the named daemon from the localhost or a remote host.
named daemon, BIND uses a shared secret key authentication method to grant privileges to hosts. This means an identical key must be present in both /etc/named.conf and the rndc configuration file, /etc/rndc.conf.
bind-chroot package, the BIND service will run in the /var/named/chroot environment. All configuration files will be moved there. As such, the rndc.conf file is located in /var/named/chroot/etc/rndc.conf.
rndc utility does not run in a chroot environment, /etc/rndc.conf is a symlink to /var/named/chroot/etc/rndc.conf.
/etc/named.conf rndc to connect to a named service, there must be a controls statement in the BIND server's /etc/named.conf file.
controls statement, shown in the following example, allows rndc to connect from the localhost.
controls {
inet 127.0.0.1
allow { localhost; } keys { <key-name>; };
};
named to listen on the default TCP port 953 of the loopback address and allow rndc commands coming from the localhost, if the proper key is given. The <key-name> specifies a name in the key statement within the /etc/named.conf file. The next example illustrates a sample key statement.
key "<key-name>" { algorithm hmac-md5; secret "<key-value>"; };
<key-value> uses the HMAC-MD5 algorithm. Use the following command to generate keys using the HMAC-MD5 algorithm:
dnssec-keygen -a hmac-md5 -b <bit-length> -n HOST <key-file-name>
<key-value> area can be found in the <key-file-name> /etc/named.conf is world-readable, it is advisable to place the key statement in a separate file, readable only by root, and then use an include statement to reference it. For example:
include "/etc/rndc.key";
/etc/rndc.conf key is the most important statement in /etc/rndc.conf.
key "<key-name>" { algorithm hmac-md5; secret "<key-value>"; };
<key-name> and <key-value> should be exactly the same as their settings in /etc/named.conf.
/etc/named.conf, add the following lines to /etc/rndc.conf.
options {
default-server localhost;
default-key "<key-name>";
};
rndc configuration file can also specify different keys for different servers, as in the following example:
server localhost {
key "<key-name>";
};
/etc/rndc.conf file.
/etc/rndc.conf file, refer to the rndc.conf man page.
rndc command takes the following form:
rndc<options><command><command-options>
rndc on a properly configured localhost, the following commands are available:
halt — Stops the named service immediately.
querylog — Logs all queries made to this nameserver.
refresh — Refreshes the nameserver's database.
reload — Reloads the zone files but keeps all other previously cached responses. This command also allows changes to zone files without losing all stored name resolutions.
reload command.
stats — Dumps the current named statistics to the /var/named/named.stats file.
stop — Stops the server gracefully, saving any dynamic update and Incremental Zone Transfers (IXFR) data before exiting.
/etc/rndc.conf file. The following options are available:
-c <configuration-file> — Specifies the alternate location of a configuration file.
-p <port-number> — Specifies a port number to use for the rndc connection other than the default port 953.
-s <server> — Specifies a server other than the default-server listed in /etc/rndc.conf.
-y <key-name> — Specifies a key other than the default-key option in /etc/rndc.conf.
rndc man page.
named to provide name resolution services or to act as an authority for a particular domain or sub-domain. However, BIND version 9 has a number of advanced features that allow for a more secure and efficient DNS service.
view statement in named.conf, BIND can present different information depending on which network a request originates from.
view statement uses the match-clients option to match IP addresses or entire networks and give them special options and zone data.
A6 zone records.
lwresd lightweight resolver daemon on all network clients. This daemon is a very efficient, caching-only nameserver which understands the new A6 and DNAME records used under IPv6. Refer to the lwresd man page for more information.
/etc/named.conf file.
named to refuse to start.
.) in zone files after all FQDNs and omit them on hostnames.
named appends the name of the zone or the $ORIGIN value to complete it.
named daemon to other nameservers, the recommended best practice is to change the firewall settings whenever possible.
<version-number> with the version of bind installed on the system:
/usr/share/doc/bind-<version-number>/ /usr/share/doc/bind-<version-number>/arm/ /usr/share/doc/bind-<version-number>/draft/ /usr/share/doc/bind-<version-number>/misc/ migration document for specific changes they must make when moving to BIND 9. The options file lists all of the options implemented in BIND 9 that are used in /etc/named.conf.
/usr/share/doc/bind-<version-number>/rfc/ man rndc — Explains the different options available when using the rndc command to control a BIND nameserver.
man named — Explores assorted arguments that can be used to control the BIND nameserver daemon.
man lwresd — Describes the purpose of and options available for the lightweight resolver daemon.
man named.conf — A comprehensive list of options available within the named configuration file.
man rndc.conf — A comprehensive list of options available within the rndc configuration file.
telnet or rsh. A related program called scp replaces older programs designed to copy files between hosts, such as rcp. Because these older applications do not encrypt passwords transmitted between the client and the server, avoid them whenever possible. Using secure methods to log into remote systems decreases the risks for both the client system and the remote host.
openssh) as well as the OpenSSH server (openssh-server) and client (openssh-clients) packages. Note, the OpenSSH packages require the OpenSSL package (openssl) which installs several important cryptographic libraries, enabling OpenSSH to provide encrypted communications.
openssh-server package is required and is dependent on the openssh package.
/etc/ssh/sshd_config. The default configuration file should be sufficient for most purposes. If you want to configure the daemon in ways not provided by the default sshd_config, read the sshd man page for a list of the keywords that can be defined in the configuration file.
/sbin/service sshd start. To stop the OpenSSH server, use the command /sbin/service sshd stop. If you want the daemon to start automatically at boot time, refer to Chapter 6, Controlling Access to Services for information on how to manage services.
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ @ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @ @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY! Someone could be eavesdropping on you right now (man-in-the-middle attack)! It is also possible that the RSA host key has just been changed.
/etc/ssh/ssh_host*key* files and restore them after the reinstall. This process retains the system's identity, and when clients try to connect to the system after the reinstall, they will not receive the warning message.
telnet
rsh
rlogin
vsftpd
chkconfig, the ncurses-based program /usr/sbin/ntsysv, or the Services Configuration Tool (system-config-services) graphical application. All of these tools require root level access.
chkconfig, /usr/sbin/ntsysv, and the Services Configuration Tool, refer to Chapter 6, Controlling Access to Services.
ssh, scp, and sftp) and one for the server daemon (sshd).
/etc/ssh/ directory:
moduli — Contains Diffie-Hellman groups used for the Diffie-Hellman key exchange which is critical for constructing a secure transport layer. When keys are exchanged at the beginning of an SSH session, a shared, secret value is created which cannot be determined by either party alone. This value is then used to provide host authentication.
ssh_config — The system-wide default SSH client configuration file. It is overridden if one is also present in the user's home directory (~/.ssh/config).
sshd_config — The configuration file for the sshd daemon.
ssh_host_dsa_key — The DSA private key used by the sshd daemon.
ssh_host_dsa_key.pub — The DSA public key used by the sshd daemon.
ssh_host_key — The RSA private key used by the sshd daemon for version 1 of the SSH protocol.
ssh_host_key.pub — The RSA public key used by the sshd daemon for version 1 of the SSH protocol.
ssh_host_rsa_key — The RSA private key used by the sshd daemon for version 2 of the SSH protocol.
ssh_host_rsa_key.pub — The RSA public key used by the sshd for version 2 of the SSH protocol.
~/.ssh/ directory:
authorized_keys — This file holds a list of authorized public keys for servers. When the client connects to a server, the server authenticates the client by checking its signed public key stored within this file.
id_dsa — Contains the DSA private key of the user.
id_dsa.pub — The DSA public key of the user.
id_rsa — The RSA private key used by ssh for version 2 of the SSH protocol.
id_rsa.pub — The RSA public key used by ssh for version 2 of the SSH protocol
identity — The RSA private key used by ssh for version 1 of the SSH protocol.
identity.pub — The RSA public key used by ssh for version 1 of the SSH protocol.
known_hosts — This file contains DSA host keys of SSH servers accessed by the user. This file is very important for ensuring that the SSH client is connecting the correct SSH server.
known_hosts file using a text editor. Before doing this, however, contact the system administrator of the SSH server to verify the server is not compromised.
ssh_config and sshd_config man pages for information concerning the various directives available in the SSH configuration files.
openssh-clients and openssh packages installed on the client machine.
ssh Commandssh command is a secure replacement for the rlogin, rsh, and telnet commands. It allows you to log in to a remote machine as well as execute commands on a remote machine.
ssh is similar to using telnet. To log in to a remote machine named penguin.example.net, type the following command at a shell prompt:
ssh penguin.example.net
ssh to a remote machine, you will see a message similar to the following:
The authenticity of host 'penguin.example.net' can't be established. DSA key fingerprint is 94:68:3a:3a:bc:f3:9a:9b:01:5d:b3:07:38:e2:11:0c. Are you sure you want to continue connecting (yes/no)?
yes to continue. This will add the server to your list of known hosts (~/.ssh/known_hosts) as seen in the following message:
Warning: Permanently added 'penguin.example.net' (RSA) to the list of known hosts.
ssh username@penguin.example.net
ssh -l username penguin.example.net.
ssh command can be used to execute a command on the remote machine without logging in to a shell prompt. The syntax is ssh hostname command . For example, if you want to execute the command ls /usr/share/doc on the remote machine penguin.example.net, type the following command at a shell prompt:
ssh penguin.example.net ls /usr/share/doc
/usr/share/doc will be displayed, and you will return to your local shell prompt.
scp Commandscp command can be used to transfer files between machines over a secure, encrypted connection. It is similar to rcp.
scp<localfile>username@tohostname:<remotefile>
<localfile> specifies the source including path to the file, such as /var/log/maillog. The <remotefile> specifies the destination, which can be a new filename such as /tmp/hostname-maillog. For the remote system, if you do not have a preceding /, the path will be relative to the home directory of username, typically /home/username/.
shadowman to the home directory of your account on penguin.example.net, type the following at a shell prompt (replace username with your username):
scp shadowman username@penguin.example.net:shadowman
shadowman to /home/username/shadowman on penguin.example.net. Alternately, you can leave off the final shadowman in the scp command.
scpusername@tohostname:<remotefile><newlocalfile>
<remotefile> specifies the source including path, and <newlocalfile> specifies the destination including path.
downloads/ to an existing directory called uploads/ on the remote machine penguin.example.net, type the following at a shell prompt:
scp downloads/* username@penguin.example.net:uploads/
sftp Commandsftp utility can be used to open a secure, interactive FTP session. It is similar to ftp except that it uses a secure, encrypted connection. The general syntax is sftp username@hostname.com . Once authenticated, you can use a set of commands similar to those used by FTP. Refer to the sftp man page for a list of these commands. To read the man page, execute the command man sftp at a shell prompt. The sftp utility is only available in OpenSSH version 2.5.0p1 and higher.
-Y option and running an X program on a local machine.
ssh -Y <user>@example.com
system-config-printer &
ssh -Llocal-port:remote-hostname:remote-portusername@hostname
mail.example.com using POP3 through an encrypted connection, use the following command:
ssh -L 1100:mail.example.com:110 mail.example.com
mail.example.com server.
mail.example.com is not running an SSH server, but another machine on the same network is, SSH can still be used to secure part of the connection. However, a slightly different command is necessary:
ssh -L 1100:mail.example.com:110 other.example.com
other.example.com. Then, other.example.com connects to port 110 on mail.example.com to check for new mail. Note, when using this technique only the connection between the client system and other.example.com SSH server is secure.
No parameter for the AllowTcpForwarding line in /etc/ssh/sshd_config and restarting the sshd service.
ssh, scp, or sftp to connect to a remote machine, you can generate an authorization key pair.
~/.ssh/authorized_keys2, ~/.ssh/known_hosts2, and /etc/ssh_known_hosts2 are obsolete. SSH Protocol 1 and 2 share the ~/.ssh/authorized_keys, ~/.ssh/known_hosts, and /etc/ssh/ssh_known_hosts files.
.ssh directory in your home directory. After reinstalling, copy this directory back to your home directory. This process can be done for all users on your system, including root.
ssh-keygen -t rsa
~/.ssh/id_rsa. Enter a passphrase different from your account password and confirm it by entering it again.
~/.ssh/id_rsa.pub. The private key is written to ~/.ssh/id_rsa. Never distribute your private key to anyone.
.ssh directory using the following command:
chmod 755 ~/.ssh
~/.ssh/id_rsa.pub into the file ~/.ssh/authorized_keys on the machine to which you want to connect. If the file ~/.ssh/authorized_keys exist, append the contents of the file ~/.ssh/id_rsa.pub to the file ~/.ssh/authorized_keys on the other machine.
authorized_keys file using the following command:
chmod 644 ~/.ssh/authorized_keys
ssh-agent with a GUI”. If you are not running the X Window System, skip to Section 8.7.3.5, “Configuring ssh-agent ”.
ssh-keygen -t dsa
~/.ssh/id_dsa. Enter a passphrase different from your account password and confirm it by entering it again.
~/.ssh/id_dsa.pub. The private key is written to ~/.ssh/id_dsa. It is important never to give anyone the private key.
.ssh directory with the following command:
chmod 755 ~/.ssh
~/.ssh/id_dsa.pub into the file ~/.ssh/authorized_keys on the machine to which you want to connect. If the file ~/.ssh/authorized_keys exist, append the contents of the file ~/.ssh/id_dsa.pub to the file ~/.ssh/authorized_keys on the other machine.
authorized_keys file using the following command:
chmod 644 ~/.ssh/authorized_keys
ssh-agent with a GUI”. If you are not running the X Window System, skip to Section 8.7.3.5, “Configuring ssh-agent ”.
ssh-keygen -t rsa1
~/.ssh/identity). Enter a passphrase different from your account password. Confirm the passphrase by entering it again.
~/.ssh/identity.pub. The private key is written to ~/.ssh/identity. Do not give anyone the private key.
.ssh directory and your key with the commands chmod 755 ~/.ssh and chmod 644 ~/.ssh/identity.pub.
~/.ssh/identity.pub into the file ~/.ssh/authorized_keys on the machine to which you wish to connect. If the file ~/.ssh/authorized_keys does not exist, you can copy the file ~/.ssh/identity.pub to the file ~/.ssh/authorized_keys on the remote machine.
ssh-agent with a GUI”. If you are not running GNOME, skip to Section 8.7.3.5, “Configuring ssh-agent ”.
ssh-agent with a GUIssh-agent utility can be used to save your passphrase so that you do not have to enter it each time you initiate an ssh or scp connection. If you are using GNOME, the gnome-ssh-askpass package contains the application used to prompt you for your passphrase when you log in to GNOME and save it until you log out of GNOME. You will not have to enter your password or passphrase for any ssh or scp connection made during that GNOME session. If you are not using GNOME, refer to Section 8.7.3.5, “Configuring ssh-agent ”.
gnome-ssh-askpass installed; you can use the command rpm -q openssh-askpass to determine if it is installed or not. If it is not installed, install it from your Fedora CD-ROM set, from a Red Hat FTP mirror site, or using Red Hat Network.
/usr/bin/ssh-add in the Startup Command text area. Set it a priority to a number higher than any existing commands to ensure that it is executed last. A good priority number for ssh-add is 70 or higher. The higher the priority number, the lower the priority. If you have other programs listed, this one should have the lowest priority. Click to exit the program.
ssh, scp, or sftp.
ssh-agent ssh-agent can be used to store your passphrase so that you do not have to enter it each time you make a ssh or scp connection. If you are not running the X Window System, follow these steps from a shell prompt. If you are running GNOME but you do not want to configure it to prompt you for your passphrase when you log in (refer to Section 8.7.3.4, “Configuring ssh-agent with a GUI”), this procedure will work in a terminal window, such as an XTerm. If you are running X but not GNOME, this procedure will work in a terminal window. However, your passphrase will only be remembered for that terminal window; it is not a global setting.
exec /usr/bin/ssh-agent $SHELL
ssh-add
ssh, scp, sftp, sshd, and ssh-keygen man pages — These man pages include information on how to use these commands as well as all the parameters that can be used with them.
[4] X11 refers to the X11R7 windowing display system, traditionally referred to as the X Window System or X. Fedora includes X11R7, an open source X Window System.
[5] DNS poisoning occurs when an intruder cracks a DNS server, pointing client systems to a maliciously duplicated host.
[6] IP spoofing occurs when an intruder sends network packets which falsely appear to be from a trusted host on the network.
[7] A multiplexed connection consists of several signals being sent over a shared, common medium. With SSH, different channels are sent over a common secure connection.
smb.conf Filesmbd, nmbd, and winbindd). Two services (smb and windbind) control how the daemons are started, stopped, and other service-related features. Each daemon is listed in detail, as well as which specific service has control over it.
smbd smbd server daemon provides file sharing and printing services to Windows clients. In addition, it is responsible for user authentication, resource locking, and data sharing through the SMB protocol. The default ports on which the server listens for SMB traffic are TCP ports 139 and 445.
smbd daemon is controlled by the smb service.
nmbd nmbd server daemon understands and replies to NetBIOS name service requests such as those produced by SMB/CIFS in Windows-based systems. These systems include Windows 95/98/ME, Windows NT, Windows 2000, Windows XP, and LanManager clients. It also participates in the browsing protocols that make up the Windows Network Neighborhood view. The default port that the server listens to for NMB traffic is UDP port 137.
nmbd daemon is controlled by the smb service.
winbindd winbind service resolves user and group information on a server running Windows NT 2000 or Windows Server 2003. This makes Windows user / group information understandable by UNIX platforms. This is achieved by using Microsoft RPC calls, Pluggable Authentication Modules (PAM), and the Name Service Switch (NSS). This allows Windows NT domain users to appear and operate as UNIX users on a UNIX machine. Though bundled with the Samba distribution, the winbind service is controlled separately from the smb service.
winbindd daemon is controlled by the winbind service and does not require the smb service to be started in order to operate. Winbindd is also used when Samba is an Active Directory member, and may also be used on a Samba domain controller (to implement nested groups and/or interdomain trust). Because winbind is a client-side service used to connect to Windows NT-based servers, further discussion of winbind is beyond the scope of this manual.
smb: in the File > Open Location bar of Nautilus to view the workgroups.
<servername> and <sharename> with the appropriate values):
smb://<servername>/<sharename>
mount -t cifs -o <username>,<password> //<servername>/<sharename> /mnt/point/
<sharename> from <servername> in the local directory /mnt/point/. For more information about mounting a samba share, refer to man mount.cifs.
/etc/samba/smb.conf) allows users to view their home directories as a Samba share. It also shares all printers configured for the system as Samba shared printers. In other words, you can attach a printer to the system and print to it from the Windows machines on your network.
/etc/samba/ directory. Any changes to these files not made using the application are preserved.
system-config-samba RPM package installed. To start the Samba Server Configuration Tool from the desktop, go to the (on the Panel) > > > or type the command system-config-samba at a shell prompt (for example, in an XTerm or a GNOME terminal).
workgroup and server string options in smb.conf.
security option. Select one of the following types of authentication.
net utility, which is part of the samba-client package. Refer to the net man page for details. This option does not configure Samba to be an ADS Controller. Specify the realm of the Kerberos server in the Kerberos Realm field.
EXAMPLE.COM.
/etc/krb5.conf file.
encrypted passwords option. Refer to Section 9.4.3, “Encrypted Passwords” for more information about encrypted Samba passwords.
guest account option.
/etc/samba/smb.conf as its configuration file. If you change this configuration file, the changes do not take effect until you restart the Samba daemon with the command service smb restart.
smb.conf file:
workgroup =WORKGROUPNAMEserver string =BRIEF COMMENT ABOUT SERVER
WORKGROUPNAME with the name of the Windows workgroup to which this machine should belong. The BRIEF COMMENT ABOUT SERVER is optional and is used as the Windows comment about the Samba system.
smb.conf file (after modifying it to reflect your needs and your system):
[sharename] comment =Insert a comment herepath =/home/share/valid users =tfox carolepublic = no writable = yes printable = no create mask = 0765
tfox and carole to read and write to the directory /home/share, on the Samba server, from a Samba client.
/sbin/service smb start
net join command before starting the smb service.
/sbin/service smb stop
restart option is a quick way of stopping and then starting Samba. This is the most reliable way to make configuration changes take effect after editing the configuration file for Samba. Note that the restart option starts the daemon even if it was not running originally.
/sbin/service smb restart
condrestart (conditional restart) option only starts smb on the condition that it is currently running. This option is useful for scripts, because it does not start the daemon if it is not running.
smb.conf file is changed, Samba automatically reloads it after a few minutes. Issuing a manual restart or reload is just as effective.
/sbin/service smb condrestart
smb.conf file can be useful in case of a failed automatic reload by the smb service. To ensure that the Samba server configuration file is reloaded without restarting the service, type the following command as root:
/sbin/service smb reload
smb service does not start automatically at boot time. To configure Samba to start at boot time, use an initscript utility, such as /sbin/chkconfig, /usr/sbin/ntsysv, or the Services Configuration Tool program. Refer to Chapter 6, Controlling Access to Services for more information regarding these tools.
smb.conf File/etc/samba/smb.conf configuration file. Although the default smb.conf file is well documented, it does not address complex topics such as LDAP, Active Directory, and the numerous domain controller implementations.
smb.conf file for a successful configuration.
smb.conf file shows a sample configuration needed to implement anonymous read-only file sharing. The security = share parameter makes a share anonymous. Note, security levels for a single Samba server cannot be mixed. The security directive is a global Samba parameter located in the [global] configuration section of the smb.conf file.
[global] workgroup = DOCS netbios name = DOCS_SRV security = share [data] comment = Documentation Samba Server path = /export read only = Yes guest only = Yes
smb.conf file shows a sample configuration needed to implement anonymous read/write file sharing. To enable anonymous read/write file sharing, set the read only directive to no. The force user and force group directives are also added to enforce the ownership of any newly placed files specified in the share.
force user) and group (force group) in the smb.conf file.
[global] workgroup = DOCS netbios name = DOCS_SRV security = share [data] comment = Data path = /export force user = docsbot force group = users read only = No guest ok = Yes
smb.conf file shows a sample configuration needed to implement an anonymous print server. Setting browseable to no as shown does not list the printer in Windows Network Neighborhood. Although hidden from browsing, configuring the printer explicitly is possible. By connecting to DOCS_SRV using NetBIOS, the client can have access to the printer if the client is also part of the DOCS workgroup. It is also assumed that the client has the correct local printer driver installed, as the use client driver directive is set to Yes. In this case, the Samba server has no responsibility for sharing printer drivers to the client.
[global] workgroup = DOCS netbios name = DOCS_SRV security = share printcap name = cups disable spools= Yes show add printer wizard = No printing = cups [printers] comment = All Printers path = /var/spool/samba guest ok = Yes printable = Yes use client driver = Yes browseable = Yes
smb.conf file shows a sample configuration needed to implement a secure read/write print server. Setting the security directive to user forces Samba to authenticate client connections. Notice the [homes] share does not have a force user or force group directive as the [public] share does. The [homes] share uses the authenticated user details for any files created as opposed to the force user and force group in [public].
[global] workgroup = DOCS netbios name = DOCS_SRV security = user printcap name = cups disable spools = Yes show add printer wizard = No printing = cups [homes] comment = Home Directories valid users = %S read only = No browseable = No [public] comment = Data path = /export force user = docsbot force group = users guest ok = Yes [printers] comment = All Printers path = /var/spool/samba printer admin = john, ed, @admins create mask = 0600 guest ok = Yes printable = Yes use client driver = Yes browseable = Yes
smb.conf file shows a sample configuration needed to implement an Active Directory domain member server. In this example, Samba authenticates users for services being run locally but is also a client of the Active Directory. Ensure that your kerberos realm parameter is shown in all caps (for example realm = EXAMPLE.COM). Since Windows 2000/2003 requires Kerberos for Active Directory authentication, the realm directive is required. If Active Directory and Kerberos are running on different servers, the password server directive may be required to help the distinction.
[global] realm = EXAMPLE.COM security = ADS encrypt passwords = yes # Optional. Use only if Samba cannot determine the Kerberos server automatically. password server = kerberos.example.com
smb.conf file on the member server
/etc/krb5.conf file, on the member server
kinit administrator@EXAMPLE.COM
kinit command is a Kerberos initialization script that references the Active Directory administrator account and Kerberos realm. Since Active Directory requires Kerberos tickets, kinit obtains and caches a Kerberos ticket-granting ticket for client/server authentication. For more information on Kerberos, the /etc/krb5.conf file, and the kinit command, refer to .
net ads join -S windows1.example.com -U administrator%password
windows1 was automatically found in the corresponding Kerberos realm (the kinit command succeeded), the net command connects to the Active Directory server using its required administrator account and password. This creates the appropriate machine account on the Active Directory and grants permissions to the Samba domain member server to join the domain.
security = ads and not security = user is used, a local password backend such as smbpasswd is not needed. Older clients that do not support security = ads are authenticated as if security = domain had been set. This change does not affect functionality and allows local users not previously in the domain.
smb.conf file shows a sample configuration needed to implement a Windows NT4-based domain member server. Becoming a member server of an NT4-based domain is similar to connecting to an Active Directory. The main difference is NT4-based domains do not use Kerberos in their authentication method, making the smb.conf file simpler. In this instance, the Samba member server functions as a pass through to the NT4-based domain server.
[global] workgroup = DOCS netbios name = DOCS_SRV security = domain [homes] comment = Home Directories valid users = %S read only = No browseable = No [public] comment = Data path = /export force user = docsbot force group = users guest ok = Yes
smb.conf file to convert the server to a Samba-based PDC. If Windows NT-based servers are upgraded to Windows 2000/2003, the smb.conf file is easily modifiable to incorporate the infrastructure change to Active Directory if needed.
smb.conf file, join the domain before starting Samba by typing the following command as root:
net rpc join -U administrator%password
-S option, which specifies the domain server hostname, does not need to be stated in the net rpc join command. Samba uses the hostname specified by the workgroup directive in the smb.conf file instead of it being stated explicitly.
tdbsam tdbsam password database backend. Planned to replace the aging smbpasswd backend, tdbsam has numerous improvements that are explained in more detail in Section 9.8, “Samba Account Information Databases”. The passdb backend directive controls which backend is to be used for the PDC.
[global]
workgroup = DOCS
netbios name = DOCS_SRV
passdb backend = tdbsam
security = user
add user script = /usr/sbin/useradd -m %u
delete user script = /usr/sbin/userdel -r %u
add group script = /usr/sbin/groupadd %g
delete group script = /usr/sbin/groupdel %g
add user to group script = /usr/sbin/usermod -G %g %u
add machine script = /usr/sbin/useradd -s /bin/false -d /dev/null -g machines %u
# The following specifies the default logon script
# Per user logon scripts can be specified in the user
# account using pdbedit logon script = logon.bat
# This sets the default profile path.
# Set per user paths with pdbedit
logon drive = H:
domain logons = Yes
os level = 35
preferred master = Yes
domain master = Yes
[homes]
comment = Home Directories
valid users = %S
read only = No
[netlogon]
comment = Network Logon Service
path = /var/lib/samba/netlogon/scripts
browseable = No
read only = No
# For profiles to work, create a user directory under the
# path shown.
mkdir -p /var/lib/samba/profiles/john
[Profiles]
comment = Roaming Profile Share
path = /var/lib/samba/profiles
read only = No
browseable = No
guest ok = Yes
profile acls = Yes
# Other resource shares ... ...
tdbsam authentication backend. LDAP is recommended in these cases.
security = user directive is not listed in the smb.conf file, it is used by Samba. If the server accepts the client's username/password, the client can then mount multiple shares without specifying a password for each instance. Samba can also accept session-based username/password requests. The client maintains multiple authentication contexts by using a unique UID for each logon.
smb.conf, the security = user directive that sets user-level security is:
[GLOBAL] ... security = user ...
smb.conf:
[GLOBAL] ... security = domain workgroup = MARKETING ...
smb.conf, the following directives make Samba an Active Directory member server:
[GLOBAL] ... security = ADS realm = EXAMPLE.COM password server = kerberos.example.com ...
smb.conf, the following directives enable Samba to operate in server security mode:
[GLOBAL] ... encrypt passwords = Yes security = server password server = "NetBIOS_of_Domain_Controller" ...
/etc/passwd type backends. With a plain text backend, all usernames and passwords are sent unencrypted between the client and the Samba server. This method is very unsecure and is not recommended for use by any means. It is possible that different Windows clients connecting to the Samba server with plain text passwords cannot support such an authentication method.
smbpasswd smbpasswd backend utilizes a plain ASCII text layout that includes the MS Windows LanMan and NT account, and encrypted password information. The smbpasswd backend lacks the storage of the Windows NT/2000/2003 SAM extended controls. The smbpasswd backend is not recommended because it does not scale well or hold any Windows information, such as RIDs for NT-based groups. The tdbsam backend solves these issues for use in a smaller database (250 users), but is still not an enterprise-class solution.
ldapsam_compat ldapsam_compat backend allows continued OpenLDAP support for use with upgraded versions of Samba. This option normally used when migrating to Samba 3.0.
tdbsam tdbsam backend provides an ideal database backend for local servers, servers that do not need built-in database replication, and servers that do not require the scalability or complexity of LDAP. The tdbsam backend includes all of the smbpasswd database information as well as the previously-excluded SAM information. The inclusion of the extended SAM data allows Samba to implement the same account and system access controls as seen with Windows NT/2000/2003-based systems.
tdbsam backend is recommended for 250 users at most. Larger organizations should require Active Directory or LDAP integration due to scalability and possible network infrastructure concerns.
ldapsam ldapsam backend provides an optimal distributed account installation method for Samba. LDAP is optimal because of its ability to replicate its database to any number of servers using the OpenLDAP slurpd daemon. LDAP databases are light-weight and scalable, and as such are preferred by large enterprises.
/usr/share/doc/samba-<version>/LDAP/samba.schema has changed. This file contains the attribute syntax definitions and objectclass definitions that the ldapsam backend will need in order to function properly.
ldapsam backend for your Samba server, you will need to configure slapd to include this schema file. Refer to Section 14.5, “The /etc/openldap/schema/ Directory” for directions on how to do this.
openldap-server package installed if you want to use the ldapsam backend.
mysqlsam mysqlsam backend uses a MySQL-based database backend. This is useful for sites that already implement MySQL. At present, mysqlsam is now packed in a module separate from Samba, and as such is not officially supported by Samba.
/etc/hosts) or DNS, must be used.
smb.conf for a local master browser (or no browsing at all) in a domain controller environment is the same as workgroup configuration.
smb.conf file in which the Samba server is serving as a WINS server:
[global] wins support = Yes
smb.conf Settingssmb.conf configuration for CUPS support:
[global] load printers = Yes printing = cups printcap name = cups [printers] comment = All Printers path = /var/spool/samba printer = IBMInfoP browseable = No public = Yes guest ok = Yes writable = No printable = Yes printer admin = @ntadmins [print$] comment = Printer Drivers Share path = /var/lib/samba/drivers write list = ed, john printer admin = ed, john
print$ share contains printer drivers for clients to access if not available locally. The print$ share is optional and may not be required depending on the organization.
browseable to Yes enables the printer to be viewed in the Windows Network Neighborhood, provided the Samba server is set up correctly in the domain/workgroup.
findsmb program is a Perl script which reports information about SMB-aware systems on a specific subnet. If no subnet is specified the local subnet is used. Items displayed include IP address, NetBIOS name, workgroup or domain name, operating system, and version.
findsmb as any valid user on a system:
findsmb
IP ADDR NETBIOS NAME WORKGROUP/OS/VERSION
------------------------------------------------------------------
10.1.59.25 VERVE [MYGROUP] [Unix] [Samba 3.0.0-15]
10.1.59.26 STATION22 [MYGROUP] [Unix] [Samba 3.0.2-7.FC1]
10.1.56.45 TREK +[WORKGROUP] [Windows 5.0] [Windows 2000 LAN Manager]
10.1.57.94 PIXEL [MYGROUP] [Unix] [Samba 3.0.0-15]
10.1.57.137 MOBILE001 [WORKGROUP] [Windows 5.0] [Windows 2000 LAN Manager]
10.1.57.141 JAWS +[KWIKIMART] [Unix] [Samba 2.2.7a-security-rollup-fix]
10.1.56.159 FRED +[MYGROUP] [Unix] [Samba 3.0.0-14.3E]
10.1.59.192 LEGION *[MYGROUP] [Unix] [Samba 2.2.7-security-rollup-fix]
10.1.56.205 NANCYN +[MYGROUP] [Unix] [Samba 2.2.7a-security-rollup-fix]
net utility is similar to the net utility used for Windows and MS-DOS. The first argument is used to specify the protocol to use when executing a command. The <protocol> ads, rap, or rpc for specifying the type of server connection. Active Directory uses ads, Win9x/NT3 uses rap, and Windows NT4/2000/2003 uses rpc. If the protocol is omitted, net automatically tries to determine it.
wakko:
net -l share -S wakko
Password:
Enumerating shared resources (exports) on remote server:
Share name Type Description
---------- ---- -----------
data Disk Wakko data share
tmp Disk Wakko tmp share
IPC$ IPC IPC Service (Samba Server)
ADMIN$ IPC IPC Service (Samba Server)
wakko:
net -l user -S wakko
root password:
User name Comment
-----------------------------
andriusb Documentation
joe Marketing
lisa Sales
nmblookup program resolves NetBIOS names into IP addresses. The program broadcasts its query on the local subnet until the target machine replies.
nmblookup trek
querying trek on 10.1.59.255
10.1.56.45 trek<00>
pdbedit program manages accounts located in the SAM database. All backends are supported including smbpasswd, LDAP, NIS+, and the tdb database library.
pdbedit -a kristinnew password: retype new password: Unix username: kristin NT username: Account Flags: [U ] User SID: S-1-5-21-1210235352-3804200048-1474496110-2012 Primary Group SID: S-1-5-21-1210235352-3804200048-1474496110-2077 Full Name: Home Directory: \\wakko\kristin HomeDir Drive: Logon Script: Profile Path: \\wakko\kristin\profile Domain: WAKKO Account desc: Workstations: Munged dial: Logon time: 0 Logoff time: Mon, 18 Jan 2038 22:14:07 GMT Kickoff time: Mon, 18 Jan 2038 22:14:07 GMT Password last set: Thu, 29 Jan 2004 08:29:28 GMT Password can change: Thu, 29 Jan 2004 08:29:28 GMT Password must change: Mon, 18 Jan 2038 22:14:07 GMTpdbedit -v -L kristinUnix username: kristin NT username: Account Flags: [U ] User SID: S-1-5-21-1210235352-3804200048-1474496110-2012 Primary Group SID: S-1-5-21-1210235352-3804200048-1474496110-2077 Full Name: Home Directory: \\wakko\kristin HomeDir Drive: Logon Script: Profile Path: \\wakko\kristin\profile Domain: WAKKO Account desc: Workstations: Munged dial: Logon time: 0 Logoff time: Mon, 18 Jan 2038 22:14:07 GMT Kickoff time: Mon, 18 Jan 2038 22:14:07 GMT Password last set: Thu, 29 Jan 2004 08:29:28 GMT Password can change: Thu, 29 Jan 2004 08:29:28 GMT Password must change: Mon, 18 Jan 2038 22:14:07 GMTpdbedit -Landriusb:505: joe:503: lisa:504: kristin:506:pdbedit -x joepdbedit -Landriusb:505: lisa:504: kristin:506:
rpcclient program issues administrative commands using Microsoft RPCs, which provide access to the Windows administration graphical user interfaces (GUIs) for systems management. This is most often used by advanced users that understand the full complexity of Microsoft RPCs.
smbcacls program modifies Windows ACLs on files and directories shared by the Samba server.
smbclient program is a versatile UNIX client which provides functionality similar to ftp.
smbcontrol <options> <destination> <messagetype> <parameters>
smbcontrol program sends control messages to running smbd or nmbd daemons. Executing smbcontrol -i runs commands interactively until a blank line or a 'q' is entered.
smbpasswd program manages encrypted passwords. This program can be run by a superuser to change any user's password as well as by an ordinary user to change their own Samba password.
smbspool program is a CUPS-compatible printing interface to Samba. Although designed for use with CUPS printers, smbspool can work with non-CUPS printers as well.
smbstatus program displays the status of current connections to a Samba server.
smbtar program performs backup and restores of Windows-based share files and directories to a local tape archive. Though similar to the tar command, the two are not compatible.
testparm program checks the syntax of the smb.conf file. If your smb.conf file is in the default location (/etc/samba/smb.conf) you do not need to specify the location. Specifying the hostname and IP address to the testparm program verifies that the hosts.allow and host.deny files are configured correctly. The testparm program also displays a summary of your smb.conf file and the server's role (stand-alone, domain, etc.) after testing. This is convenient when debugging as it excludes comments and concisely presents information for experienced administrators to read.
testparmLoad smb config files from /etc/samba/smb.conf Processing section "[homes]" Processing section "[printers]" Processing section "[tmp]" Processing section "[html]" Loaded services file OK. Server role: ROLE_STANDALONE Press enter to see a dump of your service definitions<enter># Global parameters [global] workgroup = MYGROUP server string = Samba Server security = SHARE log file = /var/log/samba/%m.log max log size = 50 socket options = TCP_NODELAY SO_RCVBUF=8192 SO_SNDBUF=8192 dns proxy = No [homes] comment = Home Directories read only = No browseable = No [printers] comment = All Printers path = /var/spool/samba printable = Yes browseable = No [tmp] comment = Wakko tmp path = /tmp guest only = Yes [html] comment = Wakko www path = /var/www/html force user = andriusb force group = users read only = No guest only = Yes
wbinfo program displays information from the winbindd daemon. The winbindd daemon must be running for wbinfo to work.
/usr/share/doc/samba-<version-number>/ — All additional files included with the Samba distribution. This includes all helper scripts, sample configuration files, and documentation.
/usr/share/doc/samba-version_number/LDAP/smbldap-tools or can be downloaded from Sourceforge.
dhcp package contains an ISC DHCP server. First, install the package as the superuser:
~]# yum install dhcp
dhcp package creates a file, /etc/dhcpd.conf, which is merely an empty configuration file:
~]# cat /etc/dhcpd.conf
#
# DHCP Server Configuration file.
# see /usr/share/doc/dhcp*/dhcpd.conf.sample
/usr/share/doc/dhcp-<version>/dhcpd.conf.sample. You should use this file to help you configure /etc/dhcpd.conf, which is explained in detail below.
/var/lib/dhcpd/dhcpd.leases to store the client lease database. Refer to Section 10.2.2, “Lease Database” for more information.
ddns-update-style ad-hoc;
ddns-update-style interim;
dhcpd.conf man page for details about the different modes.
service dhcpd restart.
omshell command provides an interactive way to connect to, query, and change the configuration of a DHCP server. By using omshell, all changes can be made while the server is running. For more information on omshell, refer to the omshell man page.
routers, subnet-mask, domain-name, domain-name-servers, and time-offset options are used for any host statements declared below it.
subnet can be declared, a subnet declaration must be included for every subnet in the network. If it is not, the DHCP server fails to start.
range declared. Clients are assigned an IP address within the range.
subnet 192.168.1.0 netmask 255.255.255.0 {
option routers 192.168.1.254;
option subnet-mask 255.255.255.0;
option domain-name "example.com";
option domain-name-servers 192.168.1.1;
option time-offset -18000; # Eastern Standard Time
range 192.168.1.10 192.168.1.100;
}
shared-network declaration as shown in Example 10.2, “Shared-network Declaration”. Parameters within the shared-network, but outside the enclosed subnet declarations, are considered to be global parameters. The name of the shared-network must be a descriptive title for the network, such as using the title 'test-lab' to describe all the subnets in a test lab environment.
shared-network name {
option domain-name "test.redhat.com";
option domain-name-servers ns1.redhat.com, ns2.redhat.com;
option routers 192.168.0.254;
more parameters for EXAMPLE shared-network
subnet 192.168.1.0 netmask 255.255.252.0 {
parameters for subnet
range 192.168.1.1 192.168.1.254;
}
subnet 192.168.2.0 netmask 255.255.252.0 {
parameters for subnet
range 192.168.2.1 192.168.2.254;
}
}
group declaration is used to apply global parameters to a group of declarations. For example, shared networks, subnets, and hosts can be grouped.
group {
option routers 192.168.1.254;
option subnet-mask 255.255.255.0;
option domain-name "example.com";
option domain-name-servers 192.168.1.1;
option time-offset -18000; # Eastern Standard Time
host apex {
option host-name "apex.example.com";
hardware ethernet 00:A0:78:8E:9E:AA;
fixed-address 192.168.1.4;
}
host raleigh {
option host-name "raleigh.example.com";
hardware ethernet 00:A1:DD:74:C3:F2;
fixed-address 192.168.1.6;
}
}
range 192.168.1.10 and 192.168.1.100 to client systems.
default-lease-time 600;
max-lease-time 7200;
option subnet-mask 255.255.255.0;
option broadcast-address 192.168.1.255;
option routers 192.168.1.254;
option domain-name-servers 192.168.1.1, 192.168.1.2;
option domain-name "example.com";
subnet 192.168.1.0 netmask 255.255.255.0 {
range 192.168.1.10 192.168.1.100;
}
hardware ethernet parameter within a host declaration. As demonstrated in Example 10.5, “Static IP Address using DHCP”, the host apex declaration specifies that the network interface card with the MAC address 00:A0:78:8E:9E:AA always receives the IP address 192.168.1.4.
host-name can also be used to assign a host name to the client.
host apex {
option host-name "apex.example.com";
hardware ethernet 00:A0:78:8E:9E:AA;
fixed-address 192.168.1.4;
}
cp /usr/share/doc/dhcp-<version-number>/dhcpd.conf.sample /etc/dhcpd.conf
<version-number> is the DHCP version number.
dhcp-options man page.
/var/lib/dhcpd/dhcpd.leases stores the DHCP client lease database. Do not change this file. DHCP lease information for each recently assigned IP address is automatically stored in the lease database. The information includes the length of the lease, to whom the IP address has been assigned, the start and end dates for the lease, and the MAC address of the network interface card that was used to retrieve the lease.
dhcpd.leases file is renamed dhcpd.leases~ and the temporary lease database is written to dhcpd.leases.
dhcpd.leases file does not exist, but it is required to start the service. Do not create a new lease file. If you do, all old leases are lost which causes many problems. The correct solution is to rename the dhcpd.leases~ backup file to dhcpd.leases and then start the daemon.
dhcpd.leases file exists. Use the command touch /var/lib/dhcpd/dhcpd.leases to create the file if it does not exist.
named service automatically checks for a dhcpd.leases file.
/sbin/service dhcpd start. To stop the DHCP server, use the command /sbin/service dhcpd stop.
/etc/sysconfig/dhcpd, add the name of the interface to the list of DHCPDARGS:
# Command line options here DHCPDARGS=eth0
/etc/sysconfig/dhcpd include:
-p <portnum> — Specifies the UDP port number on which dhcpd should listen. The default is port 67. The DHCP server transmits responses to the DHCP clients at a port number one greater than the UDP port specified. For example, if the default port 67 is used, the server listens on port 67 for requests and responses to the client on port 68. If a port is specified here and the DHCP relay agent is used, the same port on which the DHCP relay agent should listen must be specified. Refer to Section 10.2.4, “DHCP Relay Agent” for details.
-f — Runs the daemon as a foreground process. This is mostly used for debugging.
-d — Logs the DHCP server daemon to the standard error descriptor. This is mostly used for debugging. If this is not specified, the log is written to /var/log/messages.
-cf <filename> — Specifies the location of the configuration file. The default location is /etc/dhcpd.conf.
-lf <filename> — Specifies the location of the lease database file. If a lease database file already exists, it is very important that the same file be used every time the DHCP server is started. It is strongly recommended that this option only be used for debugging purposes on non-production machines. The default location is /var/lib/dhcpd/dhcpd.leases.
-q — Do not print the entire copyright message when starting the daemon.
dhcrelay) allows for the relay of DHCP and BOOTP requests from a subnet with no DHCP server on it to one or more DHCP servers on other subnets.
/etc/sysconfig/dhcrelay with the INTERFACES directive.
service dhcrelay start.
/etc/sysconfig/network file to enable networking and the configuration file for each network device in the /etc/sysconfig/network-scripts directory. In this directory, each device should have a configuration file named ifcfg-eth0, where eth0 is the network device name.
/etc/sysconfig/network file should contain the following line:
NETWORKING=yes
NETWORKING variable must be set to yes if you want networking to start at boot time.
/etc/sysconfig/network-scripts/ifcfg-eth0 file should contain the following lines:
DEVICE=eth0 BOOTPROTO=dhcp ONBOOT=yes
DHCP_HOSTNAME — Only use this option if the DHCP server requires the client to specify a hostname before receiving an IP address. (The DHCP server daemon in Fedora does not support this feature.)
PEERDNS=<answer> , where <answer> yes — Modify /etc/resolv.conf with information from the server. If using DHCP, then yes is the default.
no — Do not modify /etc/resolv.conf.
SRCADDR=<address> , where <address> USERCTL=<answer> , where <answer> yes — Non-root users are allowed to control this device.
no — Non-root users are not allowed to control this device.
dhclient and dhclient.conf man pages.
/etc/sysconfig/dhcpd and /etc/dhcpd.conf files.
/etc/sysconfig/dhcpd file to specify which network interfaces the DHCP daemon listens on. The following /etc/sysconfig/dhcpd example specifies that the DHCP daemon listens on the eth0 and eth1 interfaces:
DHCPDARGS="eth0 eth1";
eth0, eth1, and eth2 -- and it is only desired that the DHCP daemon listens on eth0, then only specify eth0 in /etc/sysconfig/dhcpd:
DHCPDARGS="eth0";
/etc/dhcpd.conf file, for a server that has two network interfaces, eth0 in a 10.0.0.0/24 network, and eth1 in a 172.16.0.0/24 network. Multiple subnet declarations allow different settings to be defined for multiple networks:
ddns-update-styleinterim; default-lease-time600; max-lease-time7200; subnet 10.0.0.0 netmask 255.255.255.0 { option subnet-mask 255.255.255.0; option routers 10.0.0.1; range 10.0.0.5 10.0.0.15; } subnet 172.16.0.0 netmask 255.255.255.0 { option subnet-mask 255.255.255.0; option routers 172.16.0.1; range 172.16.0.5 172.16.0.15; }
subnet 10.0.0.0 netmask 255.255.255.0 subnet declaration is required for every network your DHCP server is serving. Multiple subnets require multiple subnet declarations. If the DHCP server does not have a network interface in a range of a subnet declaration, the DHCP server does not serve that network.
subnet declaration, and no network interfaces are in the range of that subnet, the DHCP daemon fails to start, and an error such as the following is logged to /var/log/messages:
dhcpd: No subnet declaration for eth0 (0.0.0.0). dhcpd: ** Ignoring requests on eth0. If this is not what dhcpd: you want, please write a subnet declaration dhcpd: in your dhcpd.conf file for the network segment dhcpd: to which interface eth1 is attached. ** dhcpd: dhcpd: dhcpd: Not configured to listen on any interfaces!
option subnet-mask 255.255.255.0; option subnet-mask option defines a subnet mask, and overrides the netmask value in the subnet declaration. In simple cases, the subnet and netmask values are the same.
option routers 10.0.0.1; option routers option defines the default gateway for the subnet. This is required for systems to reach internal networks on a different subnet, as well as external networks.
range 10.0.0.5 10.0.0.15; range option specifies the pool of available IP addresses. Systems are assigned an address from the range of specified IP addresses.
dhcpd.conf(5) man page.
/etc/dhcpd.conf, the DHCP daemon fails to start.
/etc/sysconfig/dhcpd and /etc/dhcpd.conf files.
/etc/dhcpd.conf example creates two subnets, and configures an IP address for the same system, depending on which network it connects to:
ddns-update-styleinterim; default-lease-time600; max-lease-time7200; subnet 10.0.0.0 netmask 255.255.255.0 { option subnet-mask 255.255.255.0; option routers 10.0.0.1; range 10.0.0.5 10.0.0.15; } subnet 172.16.0.0 netmask 255.255.255.0 { option subnet-mask 255.255.255.0; option routers 172.16.0.1; range 172.16.0.5 172.16.0.15; } host example0 { hardware ethernet 00:1A:6B:6A:2E:0B; fixed-address 10.0.0.20; } host example1 { hardware ethernet 00:1A:6B:6A:2E:0B; fixed-address 172.16.0.20; }
host example0 host declaration defines specific parameters for a single system, such as an IP address. To configure specific parameters for multiple hosts, use multiple host declarations.
host declarations, and as such, this name can anything, as long as it is unique to other host declarations. To configure the same system for multiple networks, use a different name for each host declaration, otherwise the DHCP daemon fails to start. Systems are identified by the hardware ethernet option, not the name in the host declaration.
hardware ethernet 00:1A:6B:6A:2E:0B; hardware ethernet option identifies the system. To find this address, run the ifconfig command on the desired system, and look for the HWaddr address.
fixed-address 10.0.0.20; fixed-address option assigns a valid IP address to the system specified by the hardware ethernet option. This address must be outside the IP address pool specified with the range option.
option statements do not end with a semicolon, the DHCP daemon fails to start, and an error such as the following is logged to /var/log/messages:
/etc/dhcpd.conf line 20: semicolon expected. dhcpd: } dhcpd: ^ dhcpd: /etc/dhcpd.conf line 38: unexpected end of file dhcpd: dhcpd: ^ dhcpd: Configuration file errors encountered -- exiting
host declarations configure a single system, that has multiple network interfaces, so that each interface receives the same IP address. This configuration will not work if both network interfaces are connected to the same network at the same time:
host interface0 {
hardware ethernet 00:1a:6b:6a:2e:0b;
fixed-address 10.0.0.18;
}
host interface1 {
hardware ethernet 00:1A:6B:6A:27:3A;
fixed-address 10.0.0.18;
}
interface0 is the first network interface, and interface1 is the second interface. The different hardware ethernet options identify each interface.
host declarations, remembering to:
fixed-address for the network the host is connecting to.
host declaration unique.
host declaration is not unique, the DHCP daemon fails to start, and an error such as the following is logged to /var/log/messages:
dhcpd: /etc/dhcpd.conf line 31: host interface0: already exists dhcpd: } dhcpd: ^ dhcpd: Configuration file errors encountered -- exiting
host interface0 declarations defined in /etc/dhcpd.conf.
dhcpd man page — Describes how the DHCP daemon works.
dhcpd.conf man page — Explains how to configure the DHCP configuration file; includes some examples.
dhcpd.leases man page — Explains how to configure the DHCP leases file; includes some examples.
dhcp-options man page — Explains the syntax for declaring DHCP options in dhcpd.conf; includes some examples.
dhcrelay man page — Explains the DHCP Relay Agent and its configuration options.
/usr/share/doc/dhcp-<version>/ — Contains sample files, README files, and release notes for current versions of the DHCP service.
[8] Kudzu is a hardware probing tool run at system boot time to determine what hardware has been added or removed from the system.
httpd httpd.conf /etc/httpd/conf/httpd.conf) to aid those who require a custom configuration or need to convert a configuration file from the older Apache HTTP Server 1.3 format.
LoadModule line will need to be updated.
mod_userdir module will only act on requests if you provide a UserDir directive indicating a directory name. If you wish to maintain the procedures used in version 2.0, add the directive UserDir public_html in your configuration file.
httpd.conf file adding the necessary mod_ssl directives. Use apachectl start as apachectl startssl is unavailable in version 2.2. You can view an example of SSL configuration for httpd in conf/extra/httpd-ssl.conf.
service httpd configtest which will detect configuration errors.
/etc/httpd/conf/httpd.conf file is a modified version of the newly installed default and a saved a copy of the original configuration file is available, it may be easiest to invoke the diff command, as in the following example (logged in as root):
diff -u httpd.conf.orig httpd.conf | less
rpm2cpio and cpio commands, as in the following example:
rpm2cpio apache-<version-number>.i386.rpm | cpio -i --make
<version-number> with the version number for the apache package.
apachectl configtest
BindAddress and Port directives no longer exist; their functionality is now provided by a more flexible Listen directive.
Port 80 was set in the 1.3 version configuration file, change it to Listen 80 in the 2.0 configuration file. If Port was set to some value other than 80, then append the port number to the contents of the ServerName directive.
Port 123 ServerName www.example.com
Listen 123 ServerName www.example.com:123 prefork, worker, and perchild. Currently only the prefork and worker MPMs are available, although the perchild MPM may be available at a later date.
prefork MPM. The prefork MPM accepts the same directives as Apache HTTP Server 1.3, so the following directives may be migrated directly:
StartServers
MinSpareServers
MaxSpareServers
MaxClients
MaxRequestsPerChild
worker MPM implements a multi-process, multi-threaded server providing greater scalability. When using this MPM, requests are handled by threads, conserving system resources and allowing large numbers of requests to be served efficiently. Although some of the directives accepted by the worker MPM are the same as those accepted by the prefork MPM, the values for those directives should not be transfered directly from an Apache HTTP Server 1.3 installation. It is best to instead use the default values as a guide, then experiment to determine what values work best.
worker MPM, create the file /etc/sysconfig/httpd and add the following directive:
HTTPD=/usr/sbin/httpd.worker
AddModule and ClearModuleList directives no longer exist. These directives where used to ensure that modules could be enabled in the correct order. The Apache HTTP Server 2.0 API allows modules to specify their ordering, eliminating the need for these two directives.
LoadModule lines are no longer relevant in most cases.
LoadModule lines for modules packaged in their own RPMs (mod_ssl, php, mod_perl, and the like) are no longer necessary as they can be found in their relevant files within the /etc/httpd/conf.d/ directory.
HAVE_XXX definitions are no longer defined.
httpd.conf contains the following directive:
Include conf.d/*.conf
mod_perl, php, and mod_ssl).
ServerType — The Apache HTTP Server can only be run as ServerType standalone making this directive irrelevant.
AccessConfig and ResourceConfig — These directives have been removed as they mirror the functionality of the Include directive. If the AccessConfig and ResourceConfig directives are set, replace them with Include directives.
Include directives should be placed at the end of the httpd.conf, with the one corresponding to ResourceConfig preceding the one corresponding to AccessConfig. If using the default values, include them explicitly as conf/srm.conf and conf/access.conf files.
<VirtualHost> container. Values here also provide defaults for any <VirtualHost> containers defined.
UserDir MappingUserDir directive is used to enable URLs such as http://example.com/~bob/ to map to a subdirectory within the home directory of the user bob, such as /home/bob/public_html/. A side-effect of this feature allows a potential attacker to determine whether a given username is present on the system. For this reason, the default configuration for Apache HTTP Server 2.0 disables this directive.
UserDir mapping, change the directive in httpd.conf from:
UserDir disable
UserDir public_html
AgentLog
RefererLog
RefererIgnore
CustomLog and LogFormat directives.
FancyIndexing directive has now been removed. The same functionality is available through the FancyIndexing option within the IndexOptions directive.
VersionSort option to the IndexOptions directive causes files containing version numbers to be sorted in a more natural way. For example, httpd-2.0.6.tar appears before httpd-2.0.36.tar in a directory index page.
ReadmeName and HeaderName directives have changed from README and HEADER to README.html and HEADER.html.
CacheNegotiatedDocs directive now takes the argument on or off. Existing instances of CacheNegotiatedDocs should be replaced with CacheNegotiatedDocs on.
ErrorDocument directive, the message should be enclosed in a pair of double quotation marks ", rather than just preceded by a double quotation mark as required in Apache HTTP Server 1.3.
ErrorDocument 404 "The document was not found
ErrorDocument setting to Apache HTTP Server 2.0, use the following structure:
ErrorDocument 404 "The document was not found"
ErrorDocument directive example.
<VirtualHost> containers should be migrated in the same way as the main server section as described in Section 11.2.2.2, “Main Server Configuration”.
/etc/httpd/conf.d/ssl.conf.
mod_include. This opens up a tremendous number of possibilities with regards to how modules can be combined to achieve a specific goal.
mod_perl). Under Apache HTTP Server 2.0, the request is initially handled by the core module — which serves static files — and is then filtered by mod_perl.
PATH_INFO directive is used for a document which is handled by a module that is now implemented as a filter, as each contains trailing path information after the true file name. The core module, which initially handles the request, does not by default understand PATH_INFO and returns 404 Not Found errors for requests that contain such information. As an alternative, use the AcceptPathInfo directive to coerce the core module into accepting requests with PATH_INFO.
AcceptPathInfo on
suexec Modulemod_suexec module uses the SuexecUserGroup directive, rather than the User and Group directives, which is used for configuring virtual hosts. The User and Group directives can still be used in general, but are deprecated for configuring virtual hosts.
<VirtualHost vhost.example.com:80> User someone Group somegroup </VirtualHost>
<VirtualHost vhost.example.com:80> SuexecUserGroup someone somegroup </VirtualHost>
mod_ssl Modulemod_ssl has been moved from the httpd.conf file into the /etc/httpd/conf.d/ssl.conf file. For this file to be loaded, and for mod_ssl to work, the statement Include conf.d/*.conf must be in the httpd.conf file as described in Section 11.2.2.1.3, “Dynamic Shared Object (DSO) Support”.
ServerName directives in SSL virtual hosts must explicitly specify the port number.
<VirtualHost _default_:443> # General setup for the virtual host ServerName ssl.example.name ... </VirtualHost>
<VirtualHost _default_:443> # General setup for the virtual host ServerName ssl.host.name:443 ... </VirtualHost>
SSLLog and SSLLogLevel directives have been removed. The mod_ssl module now obeys the ErrorLog and LogLevel directives. Refer to ErrorLog and LogLevel for more information about these directives.
mod_proxy Module<Proxy> block rather than a <Directory proxy:>.
mod_proxy has been split out into the following three modules:
mod_cache
mod_disk_cache
mod_mem_cache
mod_proxy module, but it is advisable to verify each directive before migrating any cache settings.
mod_include Modulemod_include module is now implemented as a filter and is therefore enabled differently. Refer to Section 11.2.2.4, “Modules and Apache HTTP Server 2.0” for more about filters.
AddType text/html .shtml AddHandler server-parsed .shtml
AddType text/html .shtml AddOutputFilter INCLUDES .shtml
Options +Includes directive is still required for the <Directory> container or in a .htaccess file.
mod_auth_dbm and mod_auth_db Modulesmod_auth_db and mod_auth_dbm, which used Berkeley Databases and DBM databases respectively. These modules have been combined into a single module named mod_auth_dbm in Apache HTTP Server 2.0, which can access several different database formats. To migrate from mod_auth_db, configuration files should be adjusted by replacing AuthDBUserFile and AuthDBGroupFile with the mod_auth_dbm equivalents, AuthDBMUserFile and AuthDBMGroupFile. Also, the directive AuthDBMType DB must be added to indicate the type of database file in use.
mod_auth_db configuration for Apache HTTP Server 1.3:
<Location /private/> AuthType Basic AuthName "My Private Files" AuthDBUserFile /var/www/authdb require valid-user </Location>
<Location /private/> AuthType Basic AuthName "My Private Files" AuthDBMUserFile /var/www/authdb AuthDBMType DB require valid-user </Location>
AuthDBMUserFile directive can also be used in .htaccess files.
dbmmanage Perl script, used to manipulate username and password databases, has been replaced by htdbm in Apache HTTP Server 2.0. The htdbm program offers equivalent functionality and, like mod_auth_dbm, can operate a variety of database formats; the -T option can be used on the command line to specify the format to use.
dbmmanage to htdbm ” shows how to migrate from a DBM-format database to htdbm format using dbmmanage.
| Action | dbmmanage command (1.3) | Equivalent htdbm command (2.0) |
|---|---|---|
| Add user to database (using given password) |
dbmmanage authdb add username password
|
htdbm -b -TDB authdb username password
|
| Add user to database (prompts for password) |
dbmmanage authdb adduser username
|
htdbm -TDB authdb username
|
| Remove user from database |
dbmmanage authdb delete username
|
htdbm -x -TDB authdb username
|
| List users in database |
dbmmanage authdb view
|
htdbm -l -TDB authdb
|
| Verify a password |
dbmmanage authdb check username
|
htdbm -v -TDB authdb username
|
dbmmanage to htdbm -m and -s options work with both dbmmanage and htdbm, enabling the use of the MD5 or SHA1 algorithms for hashing passwords, respectively.
htdbm, the -c option must be used.
mod_perl Modulemod_perl has been moved from httpd.conf into the file /etc/httpd/conf.d/perl.conf. For this file to be loaded, and hence for mod_perl to work, the statement Include conf.d/*.conf must be included in httpd.conf as described in Section 11.2.2.1.3, “Dynamic Shared Object (DSO) Support”.
Apache:: in httpd.conf must be replaced with ModPerl::. Additionally, the manner in which handlers are registered has been changed.
mod_perl configuration:
<Directory /var/www/perl> SetHandler perl-script PerlHandler Apache::Registry Options +ExecCGI </Directory>
mod_perl for Apache HTTP Server 2.0:
<Directory /var/www/perl> SetHandler perl-script PerlResponseHandler ModPerl::Registry Options +ExecCGI </Directory>
mod_perl 1.x should work without modification with mod_perl 2.x. XS modules require recompilation and may require minor Makefile modifications.
mod_python Modulemod_python has moved from httpd.conf to the /etc/httpd/conf.d/python.conf file. For this file to be loaded, and hence for mod_python to work, the statement Include conf.d/*.conf must be in httpd.conf as described in Section 11.2.2.1.3, “Dynamic Shared Object (DSO) Support”.
httpd.conf into the file /etc/httpd/conf.d/php.conf. For this file to be loaded, the statement Include conf.d/*.conf must be in httpd.conf as described in Section 11.2.2.1.3, “Dynamic Shared Object (DSO) Support”.
register_globals to On in the file /etc/php.ini.
mod_authz_ldap Modulemod_authz_ldap module for the Apache HTTP Server. This module uses the short form of the distinguished name for a subject and the issuer of the client SSL certificate to determine the distinguished name of the user within an LDAP directory. It is also capable of authorizing users based on attributes of that user's LDAP directory entry, determining access to assets based on the user and group privileges of the asset, and denying access for users with expired passwords. The mod_ssl module is required when using the mod_authz_ldap module.
mod_authz_ldap module does not authenticate a user to an LDAP directory using an encrypted password hash. This functionality is provided by the experimental mod_auth_ldap module. Refer to the mod_auth_ldap module documentation online at http://httpd.apache.org/docs-2.0/mod/mod_auth_ldap.html for details on the status of this module.
/etc/httpd/conf.d/authz_ldap.conf file configures the mod_authz_ldap module.
/usr/share/doc/mod_authz_ldap-<version>/index.html (replacing <version> with the version number of the package) or http://authzldap.othello.ch/ for more information on configuring the mod_authz_ldap third party module.
httpd httpd package, review the Apache HTTP Server's documentation available online at http://httpd.apache.org/docs/2.2/.
httpd RPM installs the /etc/init.d/httpd script, which can be accessed using the /sbin/service command.
httpd using the apachectl control script sets the environmental variables in /etc/sysconfig/httpd and starts httpd. You can also set the environment variables using the init script.
apachectl control script as root type:
apachectl start
httpd using /sbin/service httpd start. This starts httpd but does not set the environment variables. If you are using the default Listen directive in httpd.conf, which is port 80, you will need to have root privileges to start the apache server.
apachectl stop
httpd using /sbin/service httpd stop. The restart option is a shorthand way of stopping and then starting the Apache HTTP Server.
apachectl restartor:/sbin/service httpd restart
ErrorLog if it encounters an error while starting.
httpd service does not start automatically at boot time. If you would wish to have Apache startup at boot time, you will need to add a call to apachectl in your startup files within the rc.N directory. A typical file used is rc.local. As this starts Apache as root, it is recommended to properly configure your security and authentication before adding this call.
httpd service to start up at boot time, using an initscript utility, such as /sbin/chkconfig, /usr/sbin/ntsysv, or the Services Configuration Tool program.
apachectl status
mod_status however needs to be enabled in your httpd.conf configuration file for this to work. For more details on mod_status can be found on http://httpd.apache.org/docs/2.2/mod/mod_status.html.
/etc/httpd/conf/httpd.conf configuration file for the Apache HTTP Server. It does not use the old srm.conf or access.conf configuration files; leave them empty. Through the graphical interface, you can configure directives such as virtual hosts, logging attributes, and maximum number of connections. To start the HTTD Configuration Tool, click on System > Administration > Server Settings > HTTP.
/etc/httpd/conf/httpd.conf configuration file by hand if you wish to use this tool. The HTTP Configuration Tool generates this file after you save your changes and exit the program. If you want to add additional modules or configuration options that are not available in HTTP Configuration Tool, you cannot use this tool.
DocumentRoot and cgi-bin directories.
ServerName directive in httpd.conf. The ServerName directive sets the hostname of the Web server. It is used when creating redirection URLs. If you do not define a server name, the Web server attempts to resolve it from the IP address of the system. The server name does not have to be the domain name resolved from the IP address of the server. For example, you might set the server name to www.example.com while the server's real DNS name is foo.example.com.
ServerAdmin directive in httpd.conf. If you configure the server's error pages to contain an email address, this email address is used so that users can report a problem to the server's administrator. The default value is root@localhost.
Listen directive in httpd.conf. By default, Red Hat configures the Apache HTTP Server to listen to port 80 for non-secure Web communications.
httpd can be started as a regular user.
DirectoryIndex directive. The DirectoryIndex is the default page served by the server when a user requests an index of a directory by specifying a forward slash (/) at the end of the directory name.
http://www.example.com/this_directory/, they are going to get either the DirectoryIndex page, if it exists, or a server-generated directory list. The server tries to find one of the files listed in the DirectoryIndex directive and returns the first one it finds.
If it does not find any of these files and if Options Indexes is set for that directory, the server generates and returns a list, in HTML format, of the subdirectories and files in the directory.
ErrorDocument directive. If a problem or error occurs when a client tries to connect to the Apache HTTP Server, the default action is to display the short error message shown in the Error Code column. To override this default configuration, select the error code and click the Edit button. Choose to display the default short error message. Choose to redirect the client to an external URL and enter a complete URL, including the http://, in the Location field. Choose to redirect the client to an internal URL and enter a file location under the document root for the Web server. The location must begin the a slash (/) and be relative to the Document Root.
404.html, copy 404.html to DocumentRoot/../error/404.htmlDocumentRoot is the Document Root directory that you have defined (the default is /var/www/html/). If the Document Root is left as the default location, the file should be copied to /var/www/error/404.html. Then, choose as the Behavior for 404 - Not Found error code and enter /error/404.html as the .
ServerAdmin directive.
mod_ssl enables encryption of the HTTP protocol over SSL. SSL (Secure Sockets Layer) protocol is used for communication and encryption over TCP/IP networks. The SSL tab enables you to configure SSL for your server. To configure SSL you need to provide the path to your:
SSLCertificateFile directive which points the path to the PEM (Privacy Enhanced Mail)-encoded server certificate file.
SSLCertificateKeyFile directive which points the path to the PEM-encoded server private key file.
SSLCertificateChainFile directive which points the path to the certificate file containing all the server's chain of certificates.
SSLOptions with the following options:
SSL_SERVER_CERT, SSL_CLIENT_CERT and SSL_CLIENT_CERT_CHAIN_n where n is a number 0,1,2,3,4... These files are used for more certificate checks by CGI scripts.
SSLRequireSSL and SSLRequire directives indicate access is forbiden.
mod_ssl which also performs safe parameter checks. It is recommended to enable OptRenegotiate on a per directory basis.
/var/log/httpd/access_log file and the error log to the /var/log/httpd/error_log file.
TransferLog directive.
LogFormat directive. Refer to http://httpd.apache.org/docs/2.2/mod/mod_log_config.html#logformat for details on the format of this directive.
ErrorLog directive.
LogLevel directive.
HostnameLookups directive. Choosing No Reverse Lookup sets the value to off. Choosing Reverse Lookup sets the value to on. Choosing Double Reverse Lookup sets the value to double.
mod_env module to configure the environment variables which are passed to CGI scripts and SSI pages. Use the Environment Variables page to configure the directives for this module.
MAXNUM to 50, click the button inside the Set for CGI Script section, as shown in Figure 11.8, “Environment Variables”, and type MAXNUM in the Environment Variable text field and 50 in the Value to set text field. Click to add it to the list. The Set for CGI Scripts section configures the SetEnv directive.
env at a shell prompt. Click the button inside the Pass to CGI Scripts section and enter the name of the environment variable in the resulting dialog box. Click to add it to the list. The Pass to CGI Scripts section configures the PassEnv directive.
UnsetEnv directive.
<Directory> directive.
Options directive within the <Directory> directive. You can configure the following options:
#exec and #include commands in CGI scripts.
DirectoryIndex (such as index.html) exists in the requested directory.
Order directive with the left-hand side options. The Order directive controls the order in which allow and deny directives are evaluated. In the Allow hosts from and Deny hosts from text field, you can specify one of the following:
all to allow access to all hosts.
192.168.1.0/255.255.255.0
10.3.0.0/16
.htaccess file take precedence.
httpd.conf /etc/httpd/conf/httpd.conf. The httpd.conf file is well-commented and mostly self-explanatory. The default configuration works for most situations; however, it is a good idea to become familiar some of the more important configuration options.
/etc/httpd/conf/httpd.conf and then either reload, restart, or stop and start the httpd process as outlined in Section 11.3, “Starting and Stopping httpd ”.
httpd.conf, make a copy the original file. Creating a backup makes it easier to recover from mistakes made while editing the configuration file.
httpd.conf to verify there are no typos.
/var/log/httpd/error_log. The error log may not be easy to interpret, depending on your level of expertise. However, the last entries in the error log should provide useful information.
httpd.conf. These descriptions are not exhaustive. For more information, refer to the Apache documentation online at http://httpd.apache.org/docs/2.2/.
mod_ssl directives, refer to the documentation online at http://httpd.apache.org/docs/2.2/mod/mod_ssl.html.
AccessFileName names the file which the server should use for access control information in each directory. The default is .htaccess.
AccessFileName directive, a set of Files tags apply access control to any file beginning with a .ht. These directives deny Web access to any .htaccess files (or other files which begin with .ht) for security reasons.
Action specifies a MIME content type and CGI script pair, so that when a file of that media type is requested, a particular CGI script is executed.
FancyIndexing as an IndexOptions parameter, the AddDescription directive can be used to display user-specified descriptions for certain files or file types in a server generated directory listing. The AddDescription directive supports listing specific files, wildcard expressions, or file extensions.
AddEncoding names file name extensions which should specify a particular encoding type. AddEncoding can also be used to instruct some browsers to uncompress certain files as they are downloaded.
AddHandler maps file extensions to specific handlers. For example, the cgi-script handler can be matched with the extension .cgi to automatically treat a file ending with .cgi as a CGI script. The following is a sample AddHandler directive for the .cgi extension.
AddHandler cgi-script .cgi
cgi-bin to function in any directory on the server which has the ExecCGI option within the directories container. Refer to Directory for more information about setting the ExecCGI option for a directory.
AddHandler directive is used to process server-parsed HTML and image-map files.
AddIcon specifies which icon to show in server generated directory listings for files with certain extensions. For example, the Web server is set to show the icon binary.gif for files with .bin or .exe extensions.
compressed.gif icon next to MIME encoded x-compress and x-gzip files in server generated directory listings.
text.gif next to files with a mime-type of text, in server generated directory listings.
AddLanguage associates file name extensions with specific languages. This directive is useful for Apache HTTP Servers which serve content in multiple languages based on the client Web browser's language settings.
AddType directive to define or override a default MIME type and file extension pairs. The following example directive tells the Apache HTTP Server to recognize the .tgz file extension:
AddType application/x-tar .tgz
Alias setting allows directories outside the DocumentRoot directory to be accessible. Any URL ending in the alias automatically resolves to the alias' path. By default, one alias for an icons/ directory is already set up. An icons/ directory can be accessed by the Web server, but the directory is not in the DocumentRoot.
Allow specifies which client can access a given directory. The client can be all, a domain name, an IP address, a partial IP address, a network/netmask pair, and so on. The DocumentRoot directory is configured to Allow requests from all, meaning everyone has access.
AllowOverride directive sets whether any Options can be overridden by the declarations in an .htaccess file. By default, both the root directory and the DocumentRoot are set to allow no .htaccess overrides.
BrowserMatch directive allows the server to define environment variables and take appropriate actions based on the User-Agent HTTP header field — which identifies the client's Web browser type. By default, the Web server uses BrowserMatch to deny connections to specific browsers with known problems and also to disable keepalives and HTTP header flushes for browsers that are known to have problems with those actions.
#) from the beginning of the line is sufficient. The following, however, is a list of some of the more important cache-related directives.
CacheEnable — Specifies whether the cache is a disk, memory, or file descriptor cache. By default CacheEnable configures a disk cache for URLs at or below /.
CacheRoot — Specifies the name of the directory containing cached files. The default CacheRoot is the /var/httpd/proxy/ directory.
CacheSize — Specifies how much space the cache can use in kilobytes. The default CacheSize is 5 KB.
CacheMaxExpire — Specifies how long HTML documents are retained (without a reload from the originating Web server) in the cache. The default is 24 hours (86400 seconds).
CacheLastModifiedFactor — Specifies the creation of an expiry (expiration) date for a document which did not come from its originating server with its own expiry set. The default CacheLastModifiedFactor is set to 0.1, meaning that the expiry date for such documents equals one-tenth of the amount of time since the document was last modified.
CacheDefaultExpire — Specifies the expiry time in hours for a document that was received using a protocol that does not support expiry times. The default is set to 1 hour (3600 seconds).
NoProxy — Specifies a space-separated list of subnets, IP addresses, domains, or hosts whose content is not cached. This setting is most useful for Intranet sites.
CacheNegotiatedDocs is set to on, this function is disabled and proxy servers are allowed to cache such documents.
CustomLog identifies the log file and the log file format. By default, the access log is recorded to the /var/log/httpd/access_log file while errors are recorded in the /var/log/httpd/error_log file.
CustomLog format is the combined log file format, as illustrated here:
remotehost rfc931 user date "request" status bytes referrer user-agent DefaultIcon specifies the icon displayed in server generated directory listings for files which have no other icon specified. The unknown.gif image file is the default.
DefaultType sets a default content type for the Web server to use for documents whose MIME types cannot be determined. The default is text/plain.
Deny works similar to Allow, except it specifies who is denied access. The DocumentRoot is not configured to Deny requests from anyone by default.
<Directory /path/to/directory> and </Directory> tags create a container used to enclose a group of configuration directives which apply only to a specific directory and its subdirectories. Any directive which is applicable to a directory may be used within Directory tags.
/), using the Options (refer to Options) and AllowOverride (refer to AllowOverride) directives. Under this configuration, any directory on the system which needs more permissive settings has to be explicitly given those settings.
Directory container is configured for the DocumentRoot which assigns less rigid parameters to the directory tree so that the Apache HTTP Server can access the files residing there.
Directory container can be also be used to configure additional cgi-bin directories for server-side applications outside of the directory specified in the ScriptAlias directive (refer to ScriptAlias for more information).
Directory container must set the ExecCGI option for that directory.
/home/my_cgi_directory, add the following Directory container to the httpd.conf file:
<Directory /home/my_cgi_directory> Options +ExecCGI </Directory>
AddHandler directive must be uncommented to identify files with the .cgi extension as CGI scripts. Refer to AddHandler for instructions on setting AddHandler.
DirectoryIndex is the default page served by the server when a user requests an index of a directory by specifying a forward slash (/) at the end of the directory name.
example/this_directory/, they get either the DirectoryIndex page, if it exists, or a server-generated directory list. The default for DirectoryIndex is index.html and the index.html.var type map. The server tries to find either of these files and returns the first one it finds. If it does not find one of these files and Options Indexes is set for that directory, the server generates and returns a listing, in HTML format, of the subdirectories and files within the directory, unless the directory listing feature is turned off.
DocumentRoot is the directory which contains most of the HTML files which are served in response to requests. The default DocumentRoot, for both the non-secure and secure Web servers, is the /var/www/html directory. For example, the server might receive a request for the following document:
http://example.com/foo.html
/var/www/html/foo.html
DocumentRoot so that it is not shared by the secure and the non-secure Web servers, refer to Section 11.7, “Virtual Hosts”.
ErrorDocument directive associates an HTTP response code with a message or a URL to be sent back to the client. By default, the Web server outputs a simple and usually cryptic error message when an error occurs. The ErrorDocument directive forces the Web server to instead output a customized message or page.
".
ErrorLog specifies the file where server errors are logged. By default, this directive is set to /var/log/httpd/error_log.
ExtendedStatus directive controls whether Apache generates basic (off) or detailed server status information (on), when the server-status handler is called. The server-status handler is called using Location tags. More information on calling server-status is included in Location.
Group is set to apache.
HeaderName names the file which, if it exists in the directory, is prepended to the start of server generated directory listings. Like ReadmeName, the server tries to include it as an HTML document if possible or in plain text if not.
HostnameLookups can be set to on, off, or double. If HostnameLookups is set to on, the server automatically resolves the IP address for each connection. Resolving the IP address means that the server makes one or more connections to a DNS server, adding processing overhead. If HostnameLookups is set to double, the server performs a double-reverse DNS look up adding even more processing overhead.
HostnameLookups is set to off by default.
IfDefine tags surround configuration directives that are applied if the "test" stated in the IfDefine tag is true. The directives are ignored if the test is false.
IfDefine tags is a parameter name (for example, HAVE_PERL). If the parameter is defined, meaning that it is provided as an argument to the server's start-up command, then the test is true. In this case, when the Web server is started, the test is true and the directives contained in the IfDefine tags are applied.
<IfModule> and </IfModule> tags create a conditional container which are only activated if the specified module is loaded. Directives within the IfModule container are processed under one of two conditions. The directives are processed if the module contained within the starting <IfModule> tag is loaded. Or, if an exclamation point ! appears before the module name, the directives are processed only if the module specified in the <IfModule> tag is not loaded.
ServerRoot.
mod_ssl, mod_perl, and php, the following directive must be included in Section 1: Global Environment of httpd.conf:
Include conf.d/*.conf
IndexIgnore lists file extensions, partial file names, wildcard expressions, or full file names. The Web server does not include any files which match any of those parameters in server generated directory listings.
IndexOptions controls the appearance of server generated directing listings, by adding icons, file descriptions, and so on. If Options Indexes is set (refer to Options), the Web server generates a directory listing when the Web server receives an HTTP request for a directory without an index.
DirectoryIndex directive (usually, index.html). If an index.html file is not found, Apache HTTP Server creates an HTML directory listing of the requested directory. The appearance of this directory listing is controlled, in part, by the IndexOptions directive.
FancyIndexing. This means that a user can re-sort a directory listing by clicking on column headers. Another click on the same header switches from ascending to descending order. FancyIndexing also shows different icons for different files, based upon file extensions.
AddDescription option, when used in conjunction with FancyIndexing, presents a short description for the file in server generated directory listings.
IndexOptions has a number of other parameters which can be set to control the appearance of server generated directories. The IconHeight and IconWidth parameters require the server to include HTML HEIGHT and WIDTH tags for the icons in server generated webpages. The IconsAreLinks parameter combines the graphical icon with the HTML link anchor, which contains the URL link target.
KeepAlive sets whether the server allows more than one request per connection and can be used to prevent any one client from consuming too much of the server's resources.
Keepalive is set to off. If Keepalive is set to on and the server becomes very busy, the server can quickly spawn the maximum number of child processes. In this situation, the server slows down significantly. If Keepalive is enabled, it is a good idea to set the the KeepAliveTimeout low (refer to KeepAliveTimeout for more information about the KeepAliveTimeout directive) and monitor the /var/log/httpd/error_log log file on the server. This log reports when the server is running out of child processes.
KeepAliveTimeout sets the number of seconds the server waits after a request has been served before it closes the connection. Once the server receives a request, the Timeout directive applies instead. The KeepAliveTimeout directive is set to 15 seconds by default.
LanguagePriority sets precedence for different languages in case the client Web browser has no language preference set.
Listen command identifies the ports on which the Web server accepts incoming requests. By default, the Apache HTTP Server is set to listen to port 80 for non-secure Web communications and (in the /etc/httpd/conf.d/ssl.conf file which defines any secure servers) to port 443 for secure Web communications.
httpd can be started as a regular user.
Listen directive can also be used to specify particular IP addresses over which the server accepts connections.
LoadModule is used to load Dynamic Shared Object (DSO) modules. More information on the Apache HTTP Server's DSO support, including instructions for using the LoadModule directive, can be found in Section 11.6, “Adding Modules”. Note, the load order of the modules is no longer important with Apache HTTP Server 2.0. Refer to Section 11.2.2.1.3, “Dynamic Shared Object (DSO) Support” for more information about Apache HTTP Server 2.0 DSO support.
<Location> and </Location> tags create a container in which access control based on URL can be specified.
<Location /server-status> SetHandler server-status Order deny,allow Deny from all Allow from <.example.com> </Location>
<.example.com> with the second-level domain name for the Web server.
<Location /server-info> SetHandler server-info Order deny,allow Deny from all Allow from <.example.com> </Location>
<.example.com> with the second-level domain name for the Web server.
LogFormat directive configures the format of the various Web server log files. The actual LogFormat used depends on the settings given in the CustomLog directive (refer to CustomLog).
CustomLog directive is set to combined:
%h (remote host's IP address or hostname) HostnameLookups is set to on, the client hostname is recorded unless it is not available from DNS.
%l (rfc931) %u (authenticated user) %t (date) %r (request string) %s (status) %b (bytes) %\"%{Referer}i\" (referrer) %\"%{User-Agent}i\" (user-agent) LogLevel sets how verbose the error messages in the error logs are. LogLevel can be set (from least verbose to most verbose) to emerg, alert, crit, error, warn, notice, info, or debug. The default LogLevel is warn.
MaxKeepAliveRequests is set to 100 by default, which should be appropriate for most situations.
NameVirtualHost directive associates an IP address and port number, if necessary, for any name-based virtual hosts. Name-based virtual hosting allows one Apache HTTP Server to serve different domains without using multiple IP addresses.
NameVirtualHost configuration directive and add the correct IP address. Then add additional VirtualHost containers for each virtual host as is necessary for your configuration.
Options directive controls which server features are available in a particular directory. For example, under the restrictive parameters specified for the root directory, Options is only set to the FollowSymLinks directive. No features are enabled, except that the server is allowed to follow symbolic links in the root directory.
DocumentRoot directory, Options is set to include Indexes and FollowSymLinks. Indexes permits the server to generate a directory listing for a directory if no DirectoryIndex (for example, index.html) is specified. FollowSymLinks allows the server to follow symbolic links in that directory.
Options statements from the main server configuration section need to be replicated to each VirtualHost container individually. Refer to VirtualHost for more information.
Order directive controls the order in which allow and deny directives are evaluated. The server is configured to evaluate the Allow directives before the Deny directives for the DocumentRoot directory.
PidFile names the file where the server records its process ID (PID). By default the PID is listed in /var/run/httpd.pid.
<Proxy *> and </Proxy> tags create a container which encloses a group of configuration directives meant to apply only to the proxy server. Many directives which are allowed within a <Directory> container may also be used within <Proxy> container.
#) from the beginning of the <IfModule mod_proxy.c> line, the ProxyRequests, and each line in the <Proxy> stanza. Set the ProxyRequests directive to On, and set which domains are allowed access to the server in the Allow from directive of the <Proxy> stanza.
ReadmeName names the file which, if it exists in the directory, is appended to the end of server generated directory listings. The Web server first tries to include the file as an HTML document and then tries to include it as plain text. By default, ReadmeName is set to README.html.
Redirect can be used to map the file location to a new URL. The format is as follows:
Redirect /<old-path>/<file-name> http://<current-domain>/<current-path>/<file-name>
<old-path> with the old path information for <file-name> and <current-domain> and <current-path> with the current domain and path information for <file-name>.
<file-name> at the old location is automatically redirected to the new location.
mod_rewrite module included with the Apache HTTP Server. For more information about configuring the mod_rewrite module, refer to the Apache Software Foundation documentation online at http://httpd.apache.org/docs/2.2/mod/mod_rewrite.html.
ScriptAlias directive defines where CGI scripts are located. Generally, it is not good practice to leave CGI scripts within the DocumentRoot, where they can potentially be viewed as text documents. For this reason, a special directory outside of the DocumentRoot directory containing server-side executables and scripts is designated by the ScriptAlias directive. This directory is known as a cgi-bin and is set to /var/www/cgi-bin/ by default.
cgi-bin/ directory. For instructions on doing so, refer to AddHandler and Directory.
ServerAdmin directive to the email address of the Web server administrator. This email address shows up in error messages on server-generated Web pages, so users can report a problem by sending email to the server administrator.
ServerAdmin is set to root@localhost.
ServerAdmin is to set it to webmaster@example.com. Once set, alias webmaster to the person responsible for the Web server in /etc/aliases and run /usr/bin/newaliases.
ServerName specifies a hostname and port number (matching the Listen directive) for the server. The ServerName does not need to match the machine's actual hostname. For example, the Web server may be www.example.com, but the server's hostname is actually foo.example.com. The value specified in ServerName must be a valid Domain Name Service (DNS) name that can be resolved by the system — do not make something up.
ServerName directive:
ServerName www.example.com:80
ServerName, be sure the IP address and server name pair are included in the /etc/hosts file.
ServerRoot directive specifies the top-level directory containing website content. By default, ServerRoot is set to "/etc/httpd" for both secure and non-secure servers.
ServerSignature directive adds a line containing the Apache HTTP Server server version and the ServerName to any server-generated documents, such as error messages sent back to clients. ServerSignature is set to on by default.
ServerSignature can be set to EMail which adds a mailto:ServerAdmin HTML tag to the signature line of auto-generated responses. ServerSignature can also be set to Off to stop Apache from sending out its version number and module information. Please also check the ServerTokens settings.
ServerTokens directive determines if the Server response header field sent back to clients should include details of the Operating System type and information about compiled-in modules. By default, ServerTokens is set to Full which sends information about the Operating System type and compiled-in modules. Setting the ServerTokens to Prod sends the product name only and is recommended as many hackers check information in the Server header when scanning for vulnerabilities. You can also set the ServerTokens to Min (minimal) or to OS (operating system).
SuexecUserGroup directive, which originates from the mod_suexec module, allows the specification of user and group execution privileges for CGI programs. Non-CGI requests are still processed with the user and group specified in the User and Group directives.
SuexecUserGroup directive replaced the Apache HTTP Server 1.3 configuration of using the User and Group directives inside the configuration of VirtualHosts sections.
Timeout defines, in seconds, the amount of time that the server waits for receipts and transmissions during communications. Timeout is set to 300 seconds by default, which is appropriate for most situations.
TypesConfig names the file which sets the default list of MIME type mappings (file name extensions to content types). The default TypesConfig file is /etc/mime.types. Instead of editing /etc/mime.types, the recommended way to add MIME type mappings is to use the AddType directive.
AddType, refer to AddType.
on, this directive configures the Apache HTTP Server to reference itself using the value specified in the ServerName and Port directives. When UseCanonicalName is set to off, the server instead uses the value used by the requesting client when referring to itself.
UseCanonicalName is set to off by default.
User directive sets the username of the server process and determines what files the server is allowed to access. Any files inaccessible to this user are also inaccessible to clients connecting to the Apache HTTP Server.
User is set to apache.
UserDir is the subdirectory within each user's home directory where they should place personal HTML files which are served by the Web server. This directive is set to disable by default.
public_html in the default configuration. For example, the server might receive the following request:
http://example.com/~username/foo.html
/home/username/public_html/foo.html
/home/username/ is the user's home directory (note that the default path to users' home directories may vary).
public_html directories (0755 also works). Files that are served in a users' public_html directories must be set to at least 0644.
<VirtualHost> and </VirtualHost> tags create a container outlining the characteristics of a virtual host. The VirtualHost container accepts most configuration directives.
VirtualHost container is provided in httpd.conf, which illustrates the minimum set of configuration directives necessary for each virtual host. Refer to Section 11.7, “Virtual Hosts” for more information about virtual hosts.
/etc/httpd/conf.d/ssl.conf.
/etc/httpd/conf.d/ssl.conf file can be configured to enable secure Web communications using SSL and TLS.
SetEnvIf sets environment variables based on the headers of incoming connections. It is not solely an SSL directive, though it is present in the supplied /etc/httpd/conf.d/ssl.conf file. It's purpose in this context is to disable HTTP keepalive and to allow SSL to close the connection without a closing notification from the client browser. This setting is necessary for certain browsers that do not reliably shut down the SSL connection.
IfModule container is necessary to define the server-pool for the MPM in use.
prefork and worker MPMs.
MaxClients sets a limit on the total number of server processes, or simultaneously connected clients, that can run at one time. The main purpose of this directive is to keep a runaway Apache HTTP Server from crashing the operating system. For busy servers this value should be set to a high value. The server's default is set to 150 regardless of the MPM in use. However, it is not recommended that the value for MaxClients exceeds 256 when using the prefork MPM.
MaxRequestsPerChild sets the total number of requests each child server process serves before the child dies. The main reason for setting MaxRequestsPerChild is to avoid long-lived process induced memory leaks. The default MaxRequestsPerChild for the prefork MPM is 4000 and for the worker MPM is 0.
prefork MPM. They adjust how the Apache HTTP Server dynamically adapts to the perceived load by maintaining an appropriate number of spare server processes based on the number of incoming requests. The server checks the number of servers waiting for a request and kills some if there are more than MaxSpareServers or creates some if the number of servers is less than MinSpareServers.
MinSpareServers value is 5; the default MaxSpareServers value is 20. These default settings should be appropriate for most situations. Be careful not to increase the MinSpareServers to a large number as doing so creates a heavy processing load on the server even when traffic is light.
worker MPM. They adjust how the Apache HTTP Server dynamically adapts to the perceived load by maintaining an appropriate number of spare server threads based on the number of incoming requests. The server checks the number of server threads waiting for a request and kills some if there are more than MaxSpareThreads or creates some if the number of servers is less than MinSpareThreads.
MinSpareThreads value is 25; the default MaxSpareThreads value is 75. These default settings should be appropriate for most situations. The value for MaxSpareThreads must be greater than or equal to the sum of MinSpareThreads and ThreadsPerChild, else the Apache HTTP Server automatically corrects it.
StartServers directive sets how many server processes are created upon startup. Since the Web server dynamically kills and creates server processes based on traffic load, it is not necessary to change this parameter. The Web server is set to start 8 server processes at startup for the prefork MPM and 2 for the worker MPM.
http-manual package is installed, documentation about DSOs can be found online at http://localhost/manual/mod/.
LoadModule directive within /etc/httpd/conf/httpd.conf. If the module is provided by a separate package, the line must appear within the modules configuration file in the /etc/httpd/conf.d/ directory. Refer to LoadModule for more information.
http.conf, Apache HTTP Server must be reloaded or restarted, as referred to in Section 11.3, “Starting and Stopping httpd ”.
httpd-devel package which contains the include files, the header files, as well as the APache eXtenSion (/usr/sbin/apxs) application, which uses the include files and the header files to compile DSOs.
/usr/sbin/apxs to compile the module sources outside the Apache source tree. For more information about using the /usr/sbin/apxs command, refer to the the Apache documentation online at http://httpd.apache.org/docs/2.2/dso.html as well as the apxs man page.
/usr/lib/httpd/modules/ directory. For 64-bit Red Hat Enterprise Linux hosts using the defaut 64-bit user-space, this path will be /usr/lib64/httpd/modules/. Then add a LoadModule line to the httpd.conf, using the following structure:
LoadModule <module-name> <path/to/module.so>
<module-name> is the name of the module and <path/to/module.so> is the path to the DSO.
httpd.conf as an example.
#<VirtualHost *:80> # ServerAdmin webmaster@dummy-host.example.com # DocumentRoot /www/docs/dummy-host.example.com # ServerName dummy-host.example.com # ErrorLog logs/dummy-host.example.com-error_log # CustomLog logs/dummy-host.example.com-access_log common #</VirtualHost>
#NameVirtualHost *:80 # #<VirtualHost *:80> # ServerAdmin webmaster@dummy-host.example.com # DocumentRoot /www/docs/dummy-host.example.com # ServerName dummy-host.example.com # ErrorLog logs/dummy-host.example.com-error_log # CustomLog logs/dummy-host.example.com-access_log common #</VirtualHost>
NameVirtualHost line by removing the hash mark (#) and replace the asterisk (*) with the IP address assigned to the machine.
<VirtualHost> container.
<VirtualHost> line, change the asterisk (*) to the server's IP address. Change the ServerName to a valid DNS name assigned to the machine, and configure the other directives as necessary.
<VirtualHost> container is highly customizable and accepts almost every directive available within the main server configuration.
Listen directive in the global settings section of /etc/httpd/conf/httpd.conf file.
httpd ” for further instructions.
mod_ssl security module enabled to use the OpenSSL library and toolkit. The combination of these three components are referred to in this section as the secure Web server or just as the secure server.
mod_ssl module is a security module for the Apache HTTP Server. The mod_ssl module uses the tools provided by the OpenSSL Project to add a very important feature to the Apache HTTP Server — the ability to encrypt communications. In contrast, regular HTTP communications between a browser and a Web server are sent in plain text, which could be intercepted and read by someone along the route between the browser and the server.
mod_ssl configuration file is located at /etc/httpd/conf.d/ssl.conf. For this file to be loaded, and hence for mod_ssl to work, you must have the statement Include conf.d/*.conf in the /etc/httpd/conf/httpd.conf file. This statement is included by default in the default Apache HTTP Server configuration file.
httpd httpd package contains the httpd daemon and related utilities, configuration files, icons, Apache HTTP Server modules, man pages, and other files used by the Apache HTTP Server.
mod_ssl mod_ssl package includes the mod_ssl module, which provides strong cryptography for the Apache HTTP Server via the Secure Sockets Layer (SSL) and Transport Layer Security (TLS) protocols.
openssl openssl package contains the OpenSSL toolkit. The OpenSSL toolkit implements the SSL and TLS protocols, and also includes a general purpose cryptography library.
https:// prefix is used at the beginning of the Uniform Resource Locator (URL) in the navigation bar.
/etc/pki/tls/private/server.key
/etc/pki/tls/certs/server.crt
httpsd.key) and certificate (httpsd.crt) are located in /etc/httpd/conf/. Move and rename your key and certificate so that the secure server can use them. Use the following two commands to move and rename your key and certificate files:
mv /etc/httpd/conf/httpsd.key /etc/pki/tls/private/server.key mv /etc/httpd/conf/httpsd.crt /etc/pki/tls/certs/server.crt
/sbin/service httpd start
cd command to change to the /etc/httpd/conf/ directory. Remove the fake key and certificate that were generated during the installation with the following commands:
rm ssl.key/server.keyrm ssl.crt/server.crt
crypto-utils package contains the genkey utility which you can use to generate keys as the name implies. To create your own private key, please ensure the crypto-utils package is installed. You can view more options by typing man genkey in your terminal. Assuming you wish to generate keys for www.example.com using the genkey utility, type in the following command in your terminal:
genkey www.example.com
make based process is no longer shipped with RHEL 5. This will start the genkey graphical user interface. The figure below illustrates the first screen. To navigate, use the keyboard arrow and tab keys. This windows indicates where your key will be stored and prompts you to proceed or cancel the operation. To proceed to the next step, select Next and press the Return (Enter) key.
genkey makeca on a server that has an existing key pair, an error message will be displayed as illustrated below. You need to delete your existing key file as indicated to generate a new key pair.
/etc/pki/tls/certs/www.example.com.crt
/etc/httpd/conf.d/ssl.conf. Change the SSLCertificateFile and SSLCertificateKey lines to be.
SSLCertificateFile /etc/pki/tls/certs/www.example.com.crt SSLCertificateKeyFile /etc/pki/tls/private/www.example.com.key
genkey command.
mod_ssl.
vsftpd.
vsftpd — A fast, secure FTP daemon which is the preferred FTP server for Fedora. The remainder of this chapter focuses on vsftpd.
vsftpd vsftpd) is designed from the ground up to be fast, stable, and, most importantly, secure. vsftpd is the only stand-alone FTP server distributed with Fedora, due to its ability to handle large numbers of connections efficiently and securely.
vsftpd has three primary aspects:
libcap library, tasks that usually require full root privileges can be executed more safely from a less privileged process.
chroot jail — Whenever possible, processes are change-rooted to the directory being shared; this directory is then considered a chroot jail. For example, if the directory /var/ftp/ is the primary shared directory, vsftpd reassigns /var/ftp/ to the new root directory, known as /. This disallows any potential malicious hacker activities for any directories not contained below the new root directory.
vsftpd deals with requests:
vsftpd launches unprivileged child processes to handle incoming connections. This allows the privileged, parent process to be as small as possible and handle relatively few tasks.
chroot jail — Because these child processes are unprivileged and only have access to the directory being shared, any crashed processes only allows the attacker access to the shared files.
vsftpd vsftpd RPM installs the daemon (/usr/sbin/vsftpd), its configuration and related files, as well as FTP directories onto the system. The following lists the files and directories related to vsftpd configuration:
/etc/rc.d/init.d/vsftpd — The initialization script (initscript) used by the /sbin/service command to start, stop, or reload vsftpd. Refer to Section 12.4, “Starting and Stopping vsftpd ” for more information about using this script.
/etc/pam.d/vsftpd — The Pluggable Authentication Modules (PAM) configuration file for vsftpd. This file specifies the requirements a user must meet to login to the FTP server. For more information, refer to .
/etc/vsftpd/vsftpd.conf — The configuration file for vsftpd. Refer to Section 12.5, “ vsftpd Configuration Options” for a list of important options contained within this file.
/etc/vsftpd.ftpusers — A list of users not allowed to log into vsftpd. By default, this list includes the root, bin, and daemon users, among others.
/etc/vsftpd.user_list — This file can be configured to either deny or allow access to the users listed, depending on whether the userlist_deny directive is set to YES (default) or NO in /etc/vsftpd/vsftpd.conf. If /etc/vsftpd.user_list is used to grant access to users, the usernames listed must not appear in /etc/vsftpd.ftpusers.
/var/ftp/ — The directory containing files served by vsftpd. It also contains the /var/ftp/pub/ directory for anonymous users. Both directories are world-readable, but writable only by the root user.
vsftpd vsftpd RPM installs the /etc/rc.d/init.d/vsftpd script, which can be accessed using the /sbin/service command.
/sbin/service vsftpd start
/sbin/service vsftpd stop
restart option is a shorthand way of stopping and then starting vsftpd. This is the most efficient way to make configuration changes take effect after editing the configuration file for vsftpd.
/sbin/service vsftpd restart
condrestart (conditional restart) option only starts vsftpd if it is currently running. This option is useful for scripts, because it does not start the daemon if it is not running.
/sbin/service vsftpd condrestart
vsftpd service does not start automatically at boot time. To configure the vsftpd service to start at boot time, use an initscript utility, such as /sbin/chkconfig, /usr/sbin/ntsysv, or the Services Configuration Tool program. Refer to Chapter 6, Controlling Access to Services for more information regarding these tools.
vsftpd vsftpd is by running multiple copies of the daemon, each with its own configuration file.
vsftpd to answer requests on different IP addresses, multiple copies of the daemon must be running. The first copy must be run using the vsftpd initscripts, as outlined in Section 12.4, “Starting and Stopping vsftpd ”. This copy uses the standard configuration file, /etc/vsftpd/vsftpd.conf.
/etc/vsftpd/ directory, such as /etc/vsftpd/vsftpd-site-2.conf. Each configuration file must be readable and writable only by root. Within each configuration file for each FTP server listening on an IPv4 network, the following directive must be unique:
listen_address=N.N.N.N
N.N.N.N with the unique IP address for the FTP site being served. If the site is using IPv6, use the listen_address6 directive instead.
vsftpd daemon must be launched from a root shell prompt using the following command:
vsftpd /etc/vsftpd/<configuration-file> [amp ]
<configuration-file> with the unique name for the server's configuration file, such as /etc/vsftpd/vsftpd-site-2.conf.
anon_root
local_root
vsftpd_log_file
xferlog_file
vsftpd's configuration file, refer to Section 12.5, “ vsftpd Configuration Options”.
/etc/rc.local file.
vsftpd Configuration Optionsvsftpd may not offer the level of customization other widely available FTP servers have, it offers enough options to fill most administrator's needs. The fact that it is not overly feature-laden limits configuration and programmatic errors.
vsftpd is handled by its configuration file, /etc/vsftpd/vsftpd.conf. Each directive is on its own line within the file and follows the following format:
<directive>=<value>
<directive> with a valid directive and <value> with a valid value.
<directive>, equal symbol, and the <value> in a directive.
#) and are ignored by the daemon.
vsftpd.conf.
vsftpd, refer to .
/etc/vsftpd/vsftpd.conf. All directives not explicitly found within vsftpd's configuration file are set to their default value.
vsftpd daemon.
listen — When enabled, vsftpd runs in stand-alone mode. Fedora sets this value to YES. This directive cannot be used in conjunction with the listen_ipv6 directive.
NO.
listen_ipv6 — When enabled, vsftpd runs in stand-alone mode, but listens only to IPv6 sockets. This directive cannot be used in conjunction with the listen directive.
NO.
session_support — When enabled, vsftpd attempts to maintain login sessions for each user through Pluggable Authentication Modules (PAM). Refer to for more information. If session logging is not necessary, disabling this option allows vsftpd to run with less processes and lower privileges.
YES.
anonymous_enable — When enabled, anonymous users are allowed to log in. The usernames anonymous and ftp are accepted.
YES.
banned_email_file — If the deny_email_enable directive is set to YES, this directive specifies the file containing a list of anonymous email passwords which are not permitted access to the server.
/etc/vsftpd.banned_emails.
banner_file — Specifies the file containing text displayed when a connection is established to the server. This option overrides any text specified in the ftpd_banner directive.
cmds_allowed — Specifies a comma-delimited list of FTP commands allowed by the server. All other commands are rejected.
deny_email_enable — When enabled, any anonymous user utilizing email passwords specified in the /etc/vsftpd.banned_emails are denied access to the server. The name of the file referenced by this directive can be specified using the banned_email_file directive.
NO.
ftpd_banner — When enabled, the string specified within this directive is displayed when a connection is established to the server. This option can be overridden by the banner_file directive.
vsftpd displays its standard banner.
local_enable — When enabled, local users are allowed to log into the system.
YES.
pam_service_name — Specifies the PAM service name for vsftpd.
ftp. Note, in Fedora, the value is set to vsftpd.
NO. Note, in Fedora, the value is set to YES.
userlist_deny — When used in conjunction with the userlist_enable directive and set to NO, all local users are denied access unless the username is listed in the file specified by the userlist_file directive. Because access is denied before the client is asked for a password, setting this directive to NO prevents local users from submitting unencrypted passwords over the network.
YES.
userlist_enable — When enabled, the users listed in the file specified by the userlist_file directive are denied access. Because access is denied before the client is asked for a password, users are prevented from submitting unencrypted passwords over the network.
NO, however under Fedora the value is set to YES.
userlist_file — Specifies the file referenced by vsftpd when the userlist_enable directive is enabled.
/etc/vsftpd.user_list and is created during installation.
anonymous_enable directive must be set to YES.
anon_mkdir_write_enable — When enabled in conjunction with the write_enable directive, anonymous users are allowed to create new directories within a parent directory which has write permissions.
NO.
anon_root — Specifies the directory vsftpd changes to after an anonymous user logs in.
anon_upload_enable — When enabled in conjunction with the write_enable directive, anonymous users are allowed to upload files within a parent directory which has write permissions.
NO.
anon_world_readable_only — When enabled, anonymous users are only allowed to download world-readable files.
YES.
ftp_username — Specifies the local user account (listed in /etc/passwd) used for the anonymous FTP user. The home directory specified in /etc/passwd for the user is the root directory of the anonymous FTP user.
ftp.
no_anon_password — When enabled, the anonymous user is not asked for a password.
NO.
secure_email_list_enable — When enabled, only a specified list of email passwords for anonymous logins are accepted. This is a convenient way to offer limited security to public content without the need for virtual users.
/etc/vsftpd.email_passwords. The file format is one password per line, with no trailing white spaces.
NO.
local_enable directive must be set to YES.
chmod_enable — When enabled, the FTP command SITE CHMOD is allowed for local users. This command allows the users to change the permissions on files.
YES.
chroot_list_enable — When enabled, the local users listed in the file specified in the chroot_list_file directive are placed in a chroot jail upon log in.
chroot_local_user directive, the local users listed in the file specified in the chroot_list_file directive are not placed in a chroot jail upon log in.
NO.
chroot_list_file — Specifies the file containing a list of local users referenced when the chroot_list_enable directive is set to YES.
/etc/vsftpd.chroot_list.
chroot_local_user — When enabled, local users are change-rooted to their home directories after logging in.
NO.
chroot_local_user opens up a number of security issues, especially for users with upload privileges. For this reason, it is not recommended.
guest_enable — When enabled, all non-anonymous users are logged in as the user guest, which is the local user specified in the guest_username directive.
NO.
guest_username — Specifies the username the guest user is mapped to.
ftp.
local_root — Specifies the directory vsftpd changes to after a local user logs in.
local_umask — Specifies the umask value for file creation. Note that the default value is in octal form (a numerical system with a base of eight), which includes a "0" prefix. Otherwise the value is treated as a base-10 integer.
022.
passwd_chroot_enable — When enabled in conjunction with the chroot_local_user directive, vsftpd change-roots local users based on the occurrence of the /./ in the home directory field within /etc/passwd.
NO.
user_config_dir — Specifies the path to a directory containing configuration files bearing the name of local system users that contain specific setting for that user. Any directive in the user's configuration file overrides those found in /etc/vsftpd/vsftpd.conf.
dirlist_enable — When enabled, users are allowed to view directory lists.
YES.
dirmessage_enable — When enabled, a message is displayed whenever a user enters a directory with a message file. This message resides within the current directory. The name of this file is specified in the message_file directive and is .message by default.
NO. Note, in Fedora, the value is set to YES.
force_dot_files — When enabled, files beginning with a dot (.) are listed in directory listings, with the exception of the . and .. files.
NO.
hide_ids — When enabled, all directory listings show ftp as the user and group for each file.
NO.
message_file — Specifies the name of the message file when using the dirmessage_enable directive.
.message.
text_userdb_names — When enabled, test usernames and group names are used in place of UID and GID entries. Enabling this option may slow performance of the server.
NO.
use_localtime — When enabled, directory listings reveal the local time for the computer instead of GMT.
NO.
download_enable — When enabled, file downloads are permitted.
YES.
chown_uploads — When enabled, all files uploaded by anonymous users are owned by the user specified in the chown_username directive.
NO.
chown_username — Specifies the ownership of anonymously uploaded files if the chown_uploads directive is enabled.
root.
write_enable — When enabled, FTP commands which can change the file system are allowed, such as DELE, RNFR, and STOR.
YES.
vsftpd's logging behavior.
dual_log_enable — When enabled in conjunction with xferlog_enable, vsftpd writes two files simultaneously: a wu-ftpd-compatible log to the file specified in the xferlog_file directive (/var/log/xferlog by default) and a standard vsftpd log file specified in the vsftpd_log_file directive (/var/log/vsftpd.log by default).
NO.
log_ftp_protocol — When enabled in conjunction with xferlog_enable and with xferlog_std_format set to NO, all FTP commands and responses are logged. This directive is useful for debugging.
NO.
syslog_enable — When enabled in conjunction with xferlog_enable, all logging normally written to the standard vsftpd log file specified in the vsftpd_log_file directive (/var/log/vsftpd.log by default) is sent to the system logger instead under the FTPD facility.
NO.
vsftpd_log_file — Specifies the vsftpd log file. For this file to be used, xferlog_enable must be enabled and xferlog_std_format must either be set to NO or, if xferlog_std_format is set to YES, dual_log_enable must be enabled. It is important to note that if syslog_enable is set to YES, the system log is used instead of the file specified in this directive.
/var/log/vsftpd.log.
xferlog_enable — When enabled, vsftpd logs connections (vsftpd format only) and file transfer information to the log file specified in the vsftpd_log_file directive (/var/log/vsftpd.log by default). If xferlog_std_format is set to YES, file transfer information is logged but connections are not, and the log file specified in xferlog_file (/var/log/xferlog by default) is used instead. It is important to note that both log files and log formats are used if dual_log_enable is set to YES.
NO. Note, in Fedora, the value is set to YES.
xferlog_file — Specifies the wu-ftpd-compatible log file. For this file to be used, xferlog_enable must be enabled and xferlog_std_format must be set to YES. It is also used if dual_log_enable is set to YES.
/var/log/xferlog.
xferlog_std_format — When enabled in conjunction with xferlog_enable, only a wu-ftpd-compatible file transfer log is written to the file specified in the xferlog_file directive (/var/log/xferlog by default). It is important to note that this file only logs file transfers and does not log connections to the server.
NO. Note, in Fedora, the value is set to YES.
wu-ftpd FTP server, the xferlog_std_format directive is set to YES under Fedora. However, this setting means that connections to the server are not logged.
vsftpd format and maintain a wu-ftpd-compatible file transfer log, set dual_log_enable to YES.
wu-ftpd-compatible file transfer log is not important, either set xferlog_std_format to NO, comment the line with a hash mark (#), or delete the line entirely.
vsftpd interacts with the network.
accept_timeout — Specifies the amount of time for a client using passive mode to establish a connection.
60.
anon_max_rate — Specifies the maximum data transfer rate for anonymous users in bytes per second.
0, which does not limit the transfer rate.
connect_from_port_20 When enabled, vsftpd runs with enough privileges to open port 20 on the server during active mode data transfers. Disabling this option allows vsftpd to run with less privileges, but may be incompatible with some FTP clients.
NO. Note, in Fedora, the value is set to YES.
connect_timeout — Specifies the maximum amount of time a client using active mode has to respond to a data connection, in seconds.
60.
data_connection_timeout — Specifies maximum amount of time data transfers are allowed to stall, in seconds. Once triggered, the connection to the remote client is closed.
300.
ftp_data_port — Specifies the port used for active data connections when connect_from_port_20 is set to YES.
20.
idle_session_timeout — Specifies the maximum amount of time between commands from a remote client. Once triggered, the connection to the remote client is closed.
300.
listen_address — Specifies the IP address on which vsftpd listens for network connections.
vsftpd serving different IP addresses, the configuration file for each copy of the vsftpd daemon must have a different value for this directive. Refer to Section 12.4.1, “Starting Multiple Copies of vsftpd ” for more information about multihomed FTP servers.
listen_address6 — Specifies the IPv6 address on which vsftpd listens for network connections when listen_ipv6 is set to YES.
vsftpd serving different IP addresses, the configuration file for each copy of the vsftpd daemon must have a different value for this directive. Refer to Section 12.4.1, “Starting Multiple Copies of vsftpd ” for more information about multihomed FTP servers.
listen_port — Specifies the port on which vsftpd listens for network connections.
21.
local_max_rate — Specifies the maximum rate data is transferred for local users logged into the server in bytes per second.
0, which does not limit the transfer rate.
max_clients — Specifies the maximum number of simultaneous clients allowed to connect to the server when it is running in standalone mode. Any additional client connections would result in an error message.
0, which does not limit connections.
max_per_ip — Specifies the maximum of clients allowed to connected from the same source IP address.
0, which does not limit connections.
pasv_address — Specifies the IP address for the public facing IP address of the server for servers behind Network Address Translation (NAT) firewalls. This enables vsftpd to hand out the correct return address for passive mode connections.
pasv_enable — When enabled, passive mode connects are allowed.
YES.
pasv_max_port — Specifies the highest possible port sent to the FTP clients for passive mode connections. This setting is used to limit the port range so that firewall rules are easier to create.
0, which does not limit the highest passive port range. The value must not exceed 65535.
pasv_min_port — Specifies the lowest possible port sent to the FTP clients for passive mode connections. This setting is used to limit the port range so that firewall rules are easier to create.
0, which does not limit the lowest passive port range. The value must not be lower 1024.
pasv_promiscuous — When enabled, data connections are not checked to make sure they are originating from the same IP address. This setting is only useful for certain types of tunneling.
NO.
port_enable — When enabled, active mode connects are allowed.
YES.
vsftpd, refer to the following resources.
/usr/share/doc/vsftpd-<version-number>/ directory — Replace <version-number> with the installed version of the vsftpd package. This directory contains a README with basic information about the software. The TUNING file contains basic performance tuning tips and the SECURITY/ directory contains information about the security model employed by vsftpd.
vsftpd related man pages — There are a number of man pages for the daemon and configuration files. The following lists some of the more important man pages.
man vsftpd — Describes available command line options for vsftpd.
man vsftpd.conf — Contains a detailed list of options available within the configuration file for vsftpd.
man 5 hosts_access — Describes the format and options available within the TCP wrappers configuration files: hosts.allow and hosts.deny.
vsftpd project page is a great place to locate the latest documentation and to contact the author of the software.
/usr/bin/dovecot and is provided by the dovecot package. When using a POP server, email messages are downloaded by email client applications. By default, most POP email clients are automatically configured to delete the message on the email server after it has been successfully transferred, however this setting usually can be changed.
ipop3s service or by using the /usr/sbin/stunnel program. Refer to Section 13.6.1, “Securing Communication” for more information.
/usr/bin/dovecot and is provided by the dovecot package. When using an IMAP mail server, email messages remain on the server where users can read or delete them. IMAP also allows client applications to create, rename, or delete mail directories on the server to organize and store email.
imaps service, or by using the /usr/sbin/stunnel program. Refer to Section 13.6.1, “Securing Communication” for more information.
imap-login and pop3-login processes which implement the IMAP and POP3 protocols are spawned by the master dovecot daemon included in the dovecot package. The use of IMAP and POP is configured through dovecot.conf; by default dovecot runs IMAP and POP3 together with their secure versions using SSL. To configure dovecot to use POP:
/etc/dovecot.conf to make sure protocols variable contains pop3. For example:
protocols = imap imaps pop3 pop3s
/sbin/service dovecot restart
chkconfig dovecot on
dovecot only reports that it started the IMAP server, but also starts the POP3 server.
dovecot configuration file /etc/pki/dovecot/dovecot-openssl.conf as you prefer. However in a typical installation, this file does not require modification.
/etc/pki/dovecot/certs/dovecot.pem and /etc/pki/dovecot/private/dovecot.pem.
/usr/libexec/dovecot/mkcert.sh script which creates the dovecot self signed certificates. The certificates are copied in the /etc/pki/dovecot/certs and /etc/pki/dovecot/private directories. To implement the changes, restart dovecot (/sbin/service dovecot restart).
dovecot can be found online at http://www.dovecot.org.
mail or Procmail.
pine.
/usr/sbin/sendmail.
/etc/mail/sendmail.cf. Avoid editing the sendmail.cf file directly. To make configuration changes to Sendmail, edit the /etc/mail/sendmail.mc file, back up the original /etc/mail/sendmail.cf, and use the following alternatives to generate a new configuration file:
/etc/mail (make all -C /etc/mail) to create a new /etc/mail/sendmail.cf configuration file. All other generated files in /etc/mail (db files) will be regenerated if needed. The old makemap commands are still usable. The make command will automatically be used by service sendmail start | restart | reload.
m4 macro processor to create a new /etc/mail/sendmail.cf. The m4 macro processor is not installed by default. Before using it to create /etc/mail/sendmail.cf, install the m4 package as the root user:
yum install m4
/etc/mail/ directory including:
access — Specifies which systems can use Sendmail for outbound email.
domaintable — Specifies domain name mapping.
local-host-names — Specifies aliases for the host.
mailertable — Specifies instructions that override routing for particular domains.
virtusertable — Specifies a domain-specific form of aliasing, allowing multiple virtual domains to be hosted on one machine.
/etc/mail/, such as access, domaintable, mailertable and virtusertable, must actually store their information in database files before Sendmail can use any configuration changes. Restarting the sendmail service will cause the configuration changes to take effect:
service sendmail restart
example.com domain delivered to bob@other-example.com
, add the following line to the virtusertable file:
@example.com bob@other-example.com
virtusertable.db file must be updated:
service sendmail restart
virtusertable.db file containing the new configuration.
/etc/mail/sendmail.cf file.
sendmail.cf file, it is a good idea to create a backup copy.
/etc/mail/sendmail.mc file as the root user. Once you are finished, restart the Sendmail service and, if the m4 package is installed, the m4 macro processor will automatically generate a new sendmail.cf configuration file:
service sendmail restart
sendmail.cf file does not allow Sendmail to accept network connections from any host other than the local computer. To configure Sendmail as a server for other clients, edit the /etc/mail/sendmail.mc file, and either change the address specified in the Addr= option of the DAEMON_OPTIONS directive from 127.0.0.1 to the IP address of an active network device or comment out the DAEMON_OPTIONS directive all together by placing dnl at the beginning of the line. When finished, regenerate /etc/mail/sendmail.cf by restarting the service
service sendmail restart
/etc/mail/sendmail.mc file must be reconfigured and a new /etc/mail/sendmail.cf must be generated.
/usr/share/sendmail-cf/README file before editing any files in the directories under the /usr/share/sendmail-cf directory, as they can affect the future configuration of /etc/mail/sendmail.cf files.
mail.example.com that handles all of their email and assigns a consistent return address to all outgoing mail.
user@example.com instead of user@host.example.com.
/etc/mail/sendmail.mc:
FEATURE(always_add_domain)dnl FEATURE(`masquerade_entire_domain')dnl FEATURE(`masquerade_envelope')dnl FEATURE(`allmasquerade')dnl MASQUERADE_AS(`bigcorp.com.')dnl MASQUERADE_DOMAIN(`bigcorp.com.')dnl MASQUERADE_AS(bigcorp.com)dnl
sendmail.cf using m4, this configuration makes all mail from inside the network appear as if it were sent from bigcorp.com.
x.edu) to accept messages from one party (y.com) and sent them to a different party (z.net). Now, however, Sendmail must be configured to permit any domain to relay mail through the server. To configure relay domains, edit the /etc/mail/relay-domains file and restart Sendmail.
/etc/mail/access file can be used to prevent connections from unwanted hosts. The following example illustrates how this file can be used to both block and specifically allow access to the Sendmail server:
badspammer.com ERROR:550 "Go away and do not spam us anymore" tux.badspammer.com OK 10.0 RELAY
badspammer.com is blocked with a 550 RFC-821 compliant error code, with a message sent back to the spammer. Email sent from the tux.badspammer.com sub-domain, is accepted. The last line shows that any email sent from the 10.0.*.* network can be relayed through the mail server.
/etc/mail/access.db is a database, use makemap to activate any changes. Do this using the following command as root:
makemap hash /etc/mail/access < /etc/mail/access
/usr/share/sendmail-cf/README for more information and examples.
aliases and virtusertables, on different mail servers that work together to support a medium- to enterprise-level organization. In short, LDAP abstracts the mail routing level from Sendmail and its separate configuration files to a powerful LDAP cluster that can be leveraged by many different applications.
/etc/mail/sendmail.mc to include the following:
LDAPROUTE_DOMAIN('yourdomain.com')dnl
FEATURE('ldap_routing')dnl
/usr/share/sendmail-cf/README for detailed LDAP routing configuration instructions and examples.
/etc/mail/sendmail.cf file by running m4 and again restarting Sendmail. Refer to Section 13.3.1.3, “Common Sendmail Configuration Changes” for instructions.
/usr/sbin/postfix. This daemon launches all related processes needed to handle mail delivery.
/etc/postfix/ directory. The following is a list of the more commonly used files:
access — Used for access control, this file specifies which hosts are allowed to connect to Postfix.
aliases — A configurable list required by the mail protocol.
main.cf — The global Postfix configuration file. The majority of configuration options are specified in this file.
master.cf — Specifies how Postfix interacts with various processes to accomplish mail delivery.
transport — Maps email addresses to relay hosts.
/etc/postfix/main.cf file does not allow Postfix to accept network connections from a host other than the local computer. For instructions on configuring Postfix as a server for other clients, refer to Section 13.3.2.2, “Basic Postfix Configuration”.
/etc/postfix/ directory, it may be necessary to restart the postfix service for the changes to take effect. The easiest way to do this is to type the following command:
/sbin/service postfix restart
/etc/postfix/main.cf file with a text editor, such as vi.
mydomain line by removing the hash mark (#), and replace domain.tld with the domain the mail server is servicing, such as example.com.
myorigin = $mydomain line.
myhostname line, and replace host.domain.tld with the hostname for the machine.
mydestination = $myhostname, localhost.$mydomain line.
mynetworks line, and replace 168.100.189.0/28 with a valid network setting for hosts that can connect to the server.
inet_interfaces = all line.
inet_interfaces = localhost line.
postfix service.
/etc/postfix/main.cf. Additional resources including information about LDAP and SpamAssassin integration are available online at http://www.postfix.org/.
.fetchmailrc file in the user's home directory.
.fetchmailrc file, Fetchmail checks for email on a remote server and downloads it. It then delivers it to port 25 on the local machine, using the local MTA to place the email in the correct user's spool file. If Procmail is available, it is launched to filter the email and place it in a mailbox so that it can be read by an MUA.
.fetchmailrc file is much easier. Place any desired configuration options in the .fetchmailrc file for those options to be used each time the fetchmail command is issued. It is possible to override these at the time Fetchmail is run by specifying that option on the command line.
.fetchmailrc file contains three classes of configuration options:
.fetchmailrc file, followed by one or more server options, each of which designate a different email server that Fetchmail should check. User options follow server options for each user account checking that email server. Like server options, multiple user options may be specified for use with a particular server as well as to check multiple email accounts on the same server.
.fetchmailrc file by the use of a special option verb, poll or skip, that precedes any of the server information. The poll action tells Fetchmail to use this server option when it is run, which checks for email using the specified user options. Any server options after a skip action, however, are not checked unless this server's hostname is specified when Fetchmail is invoked. The skip option is useful when testing configurations in .fetchmailrc because it only checks skipped servers when specifically invoked, and does not affect any currently working configurations.
.fetchmailrc file looks similar to the following example:
set postmaster "user1" set bouncemail poll pop.domain.com proto pop3 user 'user1' there with password 'secret' is user1 here poll mail.domain2.com user 'user5' there with password 'secret2' is user1 here user 'user7' there with password 'secret3' is user1 here
postmaster option) and all email errors are sent to the postmaster instead of the sender (bouncemail option). The set action tells Fetchmail that this line contains a global option. Then, two email servers are specified, one set to check using POP3, the other for trying various protocols to find one that works. Two users are checked using the second server option, but all email found for any user is sent to user1's mail spool. This allows multiple mailboxes to be checked on multiple servers, while appearing in a single MUA inbox. Each user's specific information begins with the user action.
.fetchmailrc file. Omitting the with password '<password>' section causes Fetchmail to ask for a password when it is launched.
fetchmail man page explains each option in detail, but the most common ones are listed here.
set action.
daemon <seconds> — Specifies daemon-mode, where Fetchmail stays in the background. Replace <seconds> with the number of seconds Fetchmail is to wait before polling the server.
postmaster — Specifies a local user to send mail to in case of delivery problems.
syslog — Specifies the log file for errors and status messages. By default, this is /var/log/maillog.
.fetchmailrc after a poll or skip action.
auth <auth-type> — Replace <auth-type> with the type of authentication to be used. By default, password authentication is used, but some protocols support other types of authentication, including kerberos_v5, kerberos_v4, and ssh. If the any authentication type is used, Fetchmail first tries methods that do not require a password, then methods that mask the password, and finally attempts to send the password unencrypted to authenticate to the server.
interval <number> — Polls the specified server every <number> port <port-number> — Replace <port-number> with the port number. This value overrides the default port number for the specified protocol.
proto <protocol> — Replace <protocol> with the protocol, such as pop3 or imap, to use when checking for messages on the server.
timeout <seconds> — Replace <seconds> with the number of seconds of server inactivity after which Fetchmail gives up on a connection attempt. If this value is not set, a default of 300 seconds is assumed.
user option (defined below).
fetchall — Orders Fetchmail to download all messages in the queue, including messages that have already been viewed. By default, Fetchmail only pulls down new messages.
fetchlimit <number> — Replace <number> with the number of messages to be retrieved before stopping.
flush — Deletes all previously viewed messages in the queue before retrieving new messages.
limit <max-number-bytes> — Replace <max-number-bytes> with the maximum size in bytes that messages are allowed to be when retrieved by Fetchmail. This option is useful with slow network links, when a large message takes too long to download.
password '<password>' — Replace <password> with the user's password.
preconnect "<command>" — Replace <command> with a command to be executed before retrieving messages for the user.
postconnect "<command>" — Replace <command> with a command to be executed after retrieving messages for the user.
ssl — Activates SSL encryption.
user "<username>" — Replace <username> with the username used by Fetchmail to retrieve messages. This option must precede all other user options.
fetchmail command mirror the .fetchmailrc configuration options. In this way, Fetchmail may be used with or without a configuration file. These options are not used on the command line by most users because it is easier to leave them in the .fetchmailrc file.
fetchmail command with other options for a particular purpose. It is possible to issue command options to temporarily override a .fetchmailrc setting that is causing an error, as any options specified at the command line override configuration file options.
fetchmail command can supply important information.
--configdump — Displays every possible option based on information from .fetchmailrc and Fetchmail defaults. No email is retrieved for any users when using this option.
-s — Executes Fetchmail in silent mode, preventing any messages, other than errors, from appearing after the fetchmail command.
-v — Executes Fetchmail in verbose mode, displaying every communication between Fetchmail and remote email servers.
-V — Displays detailed version information, lists its global options, and shows settings to be used with each user, including the email protocol and authentication method. No email is retrieved for any users when using this option.
.fetchmailrc file.
-a — Fetchmail downloads all messages from the remote email server, whether new or previously viewed. By default, Fetchmail only downloads new messages.
-k — Fetchmail leaves the messages on the remote email server after downloading them. This option overrides the default behavior of deleting messages after downloading them.
-l <max-number-bytes> — Fetchmail does not download any messages over a particular size and leaves them on the remote email server.
--quit — Quits the Fetchmail daemon process.
.fetchmailrc options can be found in the fetchmail man page.
/bin/mail command to send email containing log messages to the root user of the local system.
postfix is the default MTA.
mail. Both of the applications are considered LDAs and both move email from the MTA's spool file into the user's mailbox. However, Procmail provides a robust filtering system.
mail command, consult its man page.
/etc/procmailrc or of a .procmailrc file (also called an rc file) in the user's home directory invokes Procmail whenever an MTA receives a new message.
rc file. If a message matches a recipe, then the email is placed in a specified file, is deleted, or is otherwise processed.
/etc/procmailrc and rc files in the /etc/procmailrcs directory for default, system-wide, Procmail environmental variables and recipes. Procmail then searches for a .procmailrc file in the user's home directory. Many users also create additional rc files for Procmail that are referred to within the .procmailrc file in their home directory.
rc files exist in the /etc/ directory and no .procmailrc files exist in any user's home directory. Therefore, to use Procmail, each user must construct a .procmailrc file with specific environment variables and rules.
.procmailrc in the following format:
<env-variable>="<value>"
<env-variable> <value> DEFAULT — Sets the default mailbox where messages that do not match any recipes are placed.
DEFAULT value is the same as $ORGMAIL.
INCLUDERC — Specifies additional rc files containing more recipes for messages to be checked against. This breaks up the Procmail recipe lists into individual files that fulfill different roles, such as blocking spam and managing email lists, that can then be turned off or on by using comment characters in the user's .procmailrc file.
.procmailrc file may look like this:
MAILDIR=$HOME/Msgs INCLUDERC=$MAILDIR/lists.rc INCLUDERC=$MAILDIR/spam.rc
INCLUDERC line with a hash mark character (#).
LOCKSLEEP — Sets the amount of time, in seconds, between attempts by Procmail to use a particular lockfile. The default is eight seconds.
LOCKTIMEOUT — Sets the amount of time, in seconds, that must pass after a lockfile was last modified before Procmail assumes that the lockfile is old and can be deleted. The default is 1024 seconds.
LOGFILE — The file to which any Procmail information or error messages are written.
MAILDIR — Sets the current working directory for Procmail. If set, all other Procmail paths are relative to this directory.
ORGMAIL — Specifies the original mailbox, or another place to put the messages if they cannot be placed in the default or recipe-required location.
/var/spool/mail/$LOGNAME is used.
SUSPEND — Sets the amount of time, in seconds, that Procmail pauses if a necessary resource, such as swap space, is not available.
SWITCHRC — Allows a user to specify an external file containing additional Procmail recipes, much like the INCLUDERC option, except that recipe checking is actually stopped on the referring configuration file and only the recipes on the SWITCHRC-specified file are used.
VERBOSE — Causes Procmail to log more information. This option is useful for debugging.
LOGNAME, which is the login name; HOME, which is the location of the home directory; and SHELL, which is the default shell.
procmailrc man page.
:0<flags>: <lockfile-name>*<special-condition-character><condition-1>*<special-condition-character><condition-2>*<special-condition-character><condition-N><special-action-character><action-to-perform>
<flags> <lockfile-name> * character can further control the condition.
<action-to-perform> { }, that are performed on messages which match the recipe's conditions. Nesting blocks can be nested inside one another, providing greater control for identifying and performing actions on messages.
A — Specifies that this recipe is only used if the previous recipe without an A or a flag also matched this message.
a — Specifies that this recipe is only used if the previous recipe with an A or a flag also matched this message and was successfully completed.
B — Parses the body of the message and looks for matching conditions.
b — Uses the body in any resulting action, such as writing the message to a file or forwarding it. This is the default behavior.
c — Generates a carbon copy of the email. This is useful with delivering recipes, since the required action can be performed on the message and a copy of the message can continue being processed in the rc files.
D — Makes the egrep comparison case-sensitive. By default, the comparison process is not case-sensitive.
E — While similar to the A flag, the conditions in the recipe are only compared to the message if the immediately preceding the recipe without an E flag did not match. This is comparable to an else action.
e — The recipe is compared to the message only if the action specified in the immediately preceding recipe fails.
f — Uses the pipe as a filter.
H — Parses the header of the message and looks for matching conditions. This occurs by default.
h — Uses the header in a resulting action. This is the default behavior.
w — Tells Procmail to wait for the specified filter or program to finish, and reports whether or not it was successful before considering the message filtered.
W — Is identical to w except that "Program failure" messages are suppressed.
procmailrc man page.
:) after any flags on a recipe's first line. This creates a local lockfile based on the destination file name plus whatever has been set in the LOCKEXT global environment variable.
* character at the beginning of a recipe's condition line:
! — In the condition line, this character inverts the condition, causing a match to occur only if the condition does not match the message.
< — Checks if the message is under a specified number of bytes.
> — Checks if the message is over a specified number of bytes.
! — In the action line, this character tells Procmail to forward the message to the specified email addresses.
$ — Refers to a variable set earlier in the rc file. This is often used to set a common mailbox that is referred to by various recipes.
| — Starts a specified program to process the message.
{ and } — Constructs a nesting block, used to contain additional recipes to apply to matching messages.
grep man page.
:0: new-mail.spool
LOCKEXT environment variable. No condition is specified, so every message matches this recipe and is placed in the single spool file called new-mail.spool, located within the directory specified by the MAILDIR environment variable. An MUA can then view messages in this file.
rc files to direct messages to a default location.
:0 * ^From: spammer@domain.com /dev/null
spammer@domain.com are sent to the /dev/null device, deleting them.
/dev/null for permanent deletion. If a recipe inadvertently catches unintended messages, and those messages disappear, it becomes difficult to troubleshoot the rule.
/dev/null.
:0: * ^(From|CC|To).*tux-lug tuxlug
tux-lug@domain.com mailing list are placed in the tuxlug mailbox automatically for the MUA. Note that the condition in this example matches the message if it has the mailing list's email address on the From, CC, or To lines.
~/.procmailrc file:
INCLUDERC=/etc/mail/spamassassin/spamassassin-default.rc
/etc/mail/spamassassin/spamassassin-default.rc contains a simple Procmail rule that activates SpamAssassin for all incoming email. If an email is determined to be spam, it is tagged in the header as such and the title is prepended with the following pattern:
*****SPAM*****
:0 Hw * ^X-Spam-Status: Yes spam
spam.
spamd) and client application (spamc). Configuring SpamAssassin this way, however, requires root access to the host.
spamd daemon, type the following command as root:
/sbin/service spamassassin start
system-config-services), to turn on the spamassassin service. Refer to for more information about initscript utilities.
~/.procmailrc file. For a system-wide configuration, place it in /etc/procmailrc:
INCLUDERC=/etc/mail/spamassassin/spamassassin-spamc.rc
mutt.
mutt offer SSL-encrypted email sessions.
/etc/pki/tls/certs/ directory and type the following commands as root:
rm -f cyrus-imapd.pem make cyrus-imapd.pem
/etc/pki/tls/certs/ directory, and type the following commands as root:
rm -f ipop3d.pem make ipop3d.pem
imapd.pem and ipop3d.pem files before issuing each make command.
/sbin/service xinetd restart command to restart the xinetd daemon which controls imapd and ipop3d.
stunnel command can be used as an SSL encryption wrapper around the standard, non-secure daemons, imapd or pop3d.
stunnel program uses external OpenSSL libraries included with Fedora to provide strong cryptography and protect the connections. It is best to apply to a CA to obtain an SSL certificate, but it is also possible to create a self-signed certificate.
/etc/pki/tls/certs/ directory, and type the following command:
make stunnel.pem
stunnel command to start the imapd mail daemon using the following command:
/usr/sbin/stunnel -d 993 -l /usr/sbin/imapd imapd
pop3d using the stunnel command, type the following command:
/usr/sbin/stunnel -d 995 -l /usr/sbin/pop3d pop3d
stunnel, read the stunnel man page or refer to the documents in the /usr/share/doc/stunnel-<version-number> / directory, where <version-number> is the version number for stunnel.
sendmail and sendmail-cf packages.
/usr/share/sendmail-cf/README — Contains information on m4, file locations for Sendmail, supported mailers, how to access enhanced features, and more.
sendmail and aliases man pages contain helpful information covering various Sendmail options and the proper configuration of the Sendmail /etc/mail/aliases file.
/usr/share/doc/postfix-<version-number> — Contains a large amount of information about ways to configure Postfix. Replace <version-number> with the version number of Postfix.
/usr/share/doc/fetchmail-<version-number> — Contains a full list of Fetchmail features in the FEATURES file and an introductory FAQ document. Replace <version-number> with the version number of Fetchmail.
/usr/share/doc/procmail-<version-number> — Contains a README file that provides an overview of Procmail, a FEATURES file that explores every program feature, and an FAQ file with answers to many common configuration questions. Replace <version-number> with the version number of Procmail.
procmail — Provides an overview of how Procmail works and the steps involved with filtering email.
procmailrc — Explains the rc file format used to construct recipes.
procmailex — Gives a number of useful, real-world examples of Procmail recipes.
procmailsc — Explains the weighted scoring technique used by Procmail to match a particular recipe to a message.
/usr/share/doc/spamassassin-<version-number>/ — Contains a large amount of information pertaining to SpamAssassin. Replace <version-number> with the version number of the spamassassin package.
.procmailrc files and use Procmail scoring to decide if a particular action should be taken.
/etc/openldap/schema/ Directory/etc/openldap/schema/ directory. For more information, refer to Section 14.5, “The /etc/openldap/schema/ Directory”.
[<id>] dn: <distinguished name> <attrtype>: <attrvalue> <attrtype>: <attrvalue> <attrtype>: <attrvalue>
<attrtype>: <attrvalue> pairs as needed. A blank line indicates the end of an entry.
<attrtype> and <attrvalue> pairs must be defined in a corresponding schema file to use this information.
< and a > is a variable and can be set whenever a new LDAP entry is created. This rule does not apply, however, to <id>. The <id> is a number determined by the application used to edit the entry.
openldap — Contains the libraries necessary to run the OpenLDAP server and client applications.
openldap-clients — Contains command line tools for viewing and modifying directories on an LDAP server.
openldap-servers — Contains the servers and other utilities necessary to configure and run an LDAP server.
openldap-servers package: the Standalone LDAP Daemon (/usr/sbin/slapd) and the Standalone LDAP Update Replication Daemon (/usr/sbin/slurpd).
slapd daemon is the standalone LDAP server while the slurpd daemon is used to synchronize changes from one LDAP server to other LDAP servers on the network. The slurpd daemon is only used when dealing with multiple LDAP servers.
openldap-servers package installs the following utilities into the /usr/sbin/ directory:
slapadd — Adds entries from an LDIF file to an LDAP directory. For example, the command /usr/sbin/slapadd -l ldif-input reads in the LDIF file, ldif-input /usr/sbin/slapadd. However, the directory server runs as the ldap user. Therefore the directory server is unable to modify any files created by slapadd. To correct this issue, after using slapadd, type the following command:
chown -R ldap /var/lib/ldap
slapcat — Pulls entries from an LDAP directory in the default format, Sleepycat Software's Berkeley DB system, and saves them in an LDIF file. For example, the command /usr/sbin/slapcat -l ldif-output outputs an LDIF file called ldif-output slapindex — Re-indexes the slapd directory based on the current content. This tool should be run whenever indexing options within /etc/openldap/slapd.conf are changed.
slappasswd — Generates an encrypted user password value for use with ldapmodify or the rootpw value in the slapd configuration file, /etc/openldap/slapd.conf. Execute the /usr/sbin/slappasswd command to create the password.
slapd by issuing the /sbin/service ldap stop command before using slapadd, slapcat or slapindex. Otherwise, the integrity of the LDAP directory is at risk.
openldap-clients package installs tools into /usr/bin/ which are used to add, modify, and delete entries in an LDAP directory. These tools include the following:
ldapadd — Adds entries to an LDAP directory by accepting input via a file or standard input; ldapadd is actually a hard link to ldapmodify -a.
ldapdelete — Deletes entries from an LDAP directory by accepting user input at a shell prompt or via a file.
ldapmodify — Modifies entries in an LDAP directory, accepting input via a file or standard input.
ldappasswd — Sets the password for an LDAP user.
ldapsearch — Searches for entries in an LDAP directory using a shell prompt.
ldapcompare — Opens a connection to an LDAP server, binds, and performs a comparison using specified parameters.
ldapwhoami — Opens a connection to an LDAP server, binds, and performs a whoami operation.
ldapmodrdn — Opens a connection to an LDAP server, binds, and modifies the RDNs of entries.
ldapsearch, each of these utilities is more easily used by referencing a file containing the changes to be made rather than typing a command for each entry to be changed within an LDAP directory. The format of such a file is outlined in the man page for each utility.
nss_ldap, which enhances LDAP's ability to integrate into both Linux and other UNIX environments.
nss_ldap package provides the following modules (where <version> refers to the version of libnss_ldap in use):
/lib/libnss_ldap-<version>.so
/lib/security/pam_ldap.so
nss_ldap package provides the following modules for 64-bit architectures:
/lib64/libnss_ldap-<version>.so
/lib64/security/pam_ldap.so
libnss_ldap-<version>.so module allows applications to look up users, groups, hosts, and other information using an LDAP directory via the Nameservice Switch (NSS) interface of glibc. NSS allows applications to authenticate using LDAP in conjunction with the NIS name service and flat authentication files.
pam_ldap module allows PAM-aware applications to authenticate users using information stored in an LDAP directory. PAM-aware applications include console login, POP and IMAP mail servers, and Samba. By deploying an LDAP server on a network, all of these applications can authenticate using the same user ID and password combination, greatly simplifying administration.
php-ldap package adds LDAP support to the PHP4 HTML-embedded scripting language via the /usr/lib/php4/ldap.so module. This module allows PHP4 scripts to access information stored in an LDAP directory.
mod_authz_ldap module for the Apache HTTP Server. This module uses the short form of the distinguished name for a subject and the issuer of the client SSL certificate to determine the distinguished name of the user within an LDAP directory. It is also capable of authorizing users based on attributes of that user's LDAP directory entry, determining access to assets based on the user and group privileges of the asset, and denying access for users with expired passwords. The mod_ssl module is required when using the mod_authz_ldap module.
mod_authz_ldap module does not authenticate a user to an LDAP directory using an encrypted password hash. This functionality is provided by the experimental mod_auth_ldap module, which is not included with Fedora. Refer to the Apache Software Foundation website online at http://www.apache.org/ for details on the status of this module.
/etc/openldap/ directory. The following is a brief list highlighting the most important directories and files:
/etc/openldap/ldap.conf — This is the configuration file for all client applications which use the OpenLDAP libraries such as ldapsearch, ldapadd, Sendmail, Evolution, and Ekiga.
/etc/openldap/slapd.conf — This is the configuration file for the slapd daemon. Refer to Section 14.6.1, “Editing /etc/openldap/slapd.conf ” for more information.
/etc/openldap/schema/ directory — This subdirectory contains the schema used by the slapd daemon. Refer to Section 14.5, “The /etc/openldap/schema/ Directory” for more information.
nss_ldap package is installed, it creates a file named /etc/ldap.conf. This file is used by the PAM and NSS modules supplied by the nss_ldap package. Refer to Section 14.7, “Configuring a System to Authenticate Using OpenLDAP” for more information.
/etc/openldap/schema/ Directory/etc/openldap/schema/ directory holds LDAP definitions, previously located in the slapd.at.conf and slapd.oc.conf files. The /etc/openldap/schema/redhat/ directory holds customized schemas distributed by Red Hat for Fedora.
/etc/openldap/slapd.conf using include lines, as shown in this example:
include /etc/openldap/schema/core.schema include /etc/openldap/schema/cosine.schema include /etc/openldap/schema/inetorgperson.schema include /etc/openldap/schema/nis.schema include /etc/openldap/schema/rfc822-MailMember.schema include /etc/openldap/schema/redhat/autofs.schema
local.schema file in the /etc/openldap/schema/ directory. Reference this new schema within slapd.conf by adding the following line below the default include schema lines:
include /etc/openldap/schema/local.schema
local.schema file. Many organizations use existing attribute types from the schema files installed by default and add new object classes to the local.schema file.
openldap, openldap-servers, and openldap-clients RPMs.
/etc/openldap/slapd.conf file to specify the LDAP domain and server. Refer to Section 14.6.1, “Editing /etc/openldap/slapd.conf ” for more information.
slapd with the command:
/sbin/service ldap start
chkconfig, /usr/sbin/ntsysv, or the Services Configuration Tool to configure LDAP to start at boot time. For more information about configuring services, refer to Chapter 6, Controlling Access to Services.
ldapadd.
ldapsearch to determine if slapd is accessing the information correctly.
/etc/openldap/slapd.conf slapd LDAP server, modify its configuration file, /etc/openldap/slapd.conf, to specify the correct domain and server.
suffix line names the domain for which the LDAP server provides information and should be changed from:
suffix "dc=your-domain,dc=com"
suffix "dc=example,dc=com"
rootdn entry is the Distinguished Name (DN) for a user who is unrestricted by access controls or administrative limit parameters set for operations on the LDAP directory. The rootdn user can be thought of as the root user for the LDAP directory. In the configuration file, change the rootdn line from its default value as in the following example:
rootdn "cn=root,dc=example,dc=com"
rootpw line — replacing the default value with an encrypted password string. To create an encrypted password string, type the following command:
slappasswd
/etc/openldap/slapd.conf on one of the rootpw lines and remove the hash mark (#).
rootpw {SSHA}vv2y+i6V6esazrIv70xSSnNAJE18bb2u
rootpw directive specified in /etc/openldap/slapd.conf, are sent over the network unencrypted, unless TLS encryption is enabled.
/etc/openldap/slapd.conf and refer to the man page for slapd.conf.
rootpw directive should be commented out after populating the LDAP directory by preceding it with a hash mark (#).
/usr/sbin/slapadd command line tool locally to populate the LDAP directory, use of the rootpw directive is not necessary.
/usr/sbin/slapadd. However, the directory server runs as the ldap user. Therefore, the directory server is unable to modify any files created by slapadd. To correct this issue, after using slapadd, type the following command:
chown -R ldap /var/lib/ldap
openldap-servers package.
openldap, openldap-clients, and nss_ldap packages need to be installed on all LDAP client machines.
/etc/openldap/slapd.conf file on the LDAP server to make sure it matches the specifics of the organization. Refer to Section 14.6.1, “Editing /etc/openldap/slapd.conf ” for instructions about editing slapd.conf.
/etc/ldap.conf and /etc/openldap/ldap.conf need to contain the proper server and search base information for the organization.
system-config-authentication) and select Enable LDAP Support under the User Information tab.
/etc/nsswitch.conf must be edited to use LDAP.
system-config-authentication) and select Enable LDAP Support under the User Information tab.
/etc/nsswitch.conf by hand, add ldap to the appropriate lines.
passwd: files ldap shadow: files ldap group: files ldap
system-config-authentication) and select Enable LDAP Support under the the Authentication tab. For more about configuring PAM, refer to and the PAM man pages.
/usr/share/openldap/migration/ directory contains a set of shell and Perl scripts for migrating authentication information into an LDAP format.
migrate_common.ph file so that it reflects the correct domain. The default DNS domain should be changed from its default value to something like:
$DEFAULT_MAIL_DOMAIN = "example";
$DEFAULT_BASE = "dc=example,dc=com";
README and the migration-tools.txt files in the /usr/share/openldap/migration/ directory provide more details on how to migrate the information.
| Existing name service | Is LDAP running? | Script to Use |
|---|---|---|
/etc flat files
| yes |
migrate_all_online.sh
|
/etc flat files
| no |
migrate_all_offline.sh
|
| NetInfo | yes |
migrate_all_netinfo_online.sh
|
| NetInfo | no |
migrate_all_netinfo_offline.sh
|
| NIS (YP) | yes |
migrate_all_nis_online.sh
|
| NIS (YP) | no |
migrate_all_nis_offline.sh
|
/usr/sbin/slapcat -l ldif-output . This outputs an LDIF file called ldif-output /usr/sbin/slapadd -l ldif-output .
/usr/share/docs/openldap-<versionnumber>/ directory — Contains a general README document and miscellaneous information.
man ldapadd — Describes how to add entries to an LDAP directory.
man ldapdelete — Describes how to delete entries within an LDAP directory.
man ldapmodify — Describes how to modify entries within an LDAP directory.
man ldapsearch — Describes how to search for entries within an LDAP directory.
man ldappasswd — Describes how to set or change the password of an LDAP user.
man ldapcompare — Describes how to use the ldapcompare tool.
man ldapwhoami — Describes how to use the ldapwhoami tool.
man ldapmodrdn — Describes how to modify the RDNs of entries.
man slapd — Describes command line options for the LDAP server.
man slurpd — Describes command line options for the LDAP replication server.
man slapadd — Describes command line options used to add entries to a slapd database.
man slapcat — Describes command line options used to generate an LDIF file from a slapd database.
man slapindex — Describes command line options used to regenerate an index based upon the contents of a slapd database.
man slappasswd — Describes command line options used to generate user passwords for LDAP directories.
man ldap.conf — Describes the format and options available within the configuration file for LDAP clients.
man slapd.conf — Describes the format and options available within the configuration file referenced by both the LDAP server applications (slapd and slurpd) and the LDAP administrative tools (slapadd, slapcat, and slapindex).
nsswitch.conf file configuration, with which you can only request user information from a single server of any particular type (LDAP, NIS, etc.). With SSSD, you can create multiple domains of the same, or of different types of identity provider.
/var/lib/sss/db/ directory.
cache_DOMAINNAME.ldb.
kate in the ldap.example.com domain from the user kate in the ldap.myhome.com domain. You can use SSSD to make requests using fully-qualified usernames. If you request information for kate, you will receive the information from whichever domain is listed first in the look-up order. If you request information for kate@ldap.myhome.com, however, you will receive the correct user information.
# yum install sssd
config_file_version parameter during the startup procedure. If this value is correct, the installation continues,otherwise it aborts.
/etc/sssd/sssd.conf file to the new format, and copy the existing version to /etc/sssd/sssd.conf.bak.
upgrade_config.py [
-f INFILE
] [
-o OUTFILE
] [
-verbose
] [
--no-backup
]
-f INFILE — the configuration file to upgrade. If not specified, this defaults to /etc/sssd/sssd.conf
-o OUTFILE — the name of the upgraded configuration file. If not specified, this defaults to /etc/sssd/sssd.conf
-verbose — produce more verbose output during the upgrade process
--no-backup — do not produce a back-up file. If not specified, this defaults to INFILE.bakservice command or the /etc/init.d/sssd script to control SSSD. For example, run the following command to start sssd:
# service sssd start
chkconfig command to change this behavior. For example, run the following command to configure SSSD to start when the machine boots:
# chkconfig sssd on
/etc/sssd/sssd.conf file. This file consists of various sections, each of which contains a number of key/value pairs. Some keys accept multiple values; use commas to separate multiple values for such keys. This configuration file uses data types of string, integer and Boolean (with values of TRUE or FALSE). Comments are indicated by either a hash sign (#) or a semicolon (;) in the first column. The following example illustrates some of this syntax:
[section] # Keys with single values key1 = value key2 = val2 # Keys with multiple values key10 = val10,val11
-c (or --config) parameter on the command line to specify a different configuration file for SSSD.
nss_sss, so that you can configure your system to use SSSD to retrieve user information. Edit the /etc/nsswitch.conf file for your system to use the sss name database. For example:
passwd: files sss group: files sss
/etc/pam.d/system-auth file. Edit this file to reflect the following example, and then restart sssd:
#%PAM-1.0 # This file is auto-generated. # User changes will be destroyed the next time authconfig is run. auth required pam_env.so auth sufficient pam_unix.so nullok try_first_pass auth requisite pam_succeed_if.so uid >= 500 quiet auth sufficient pam_sss.so use_first_pass auth required pam_deny.so account required pam_unix.so broken_shadow account sufficient pam_localuser.so account sufficient pam_succeed_if.so uid < 500 quiet account [default=bad success=ok user_unknown=ignore] pam_sss.so account required pam_permit.so password requisite pam_cracklib.so try_first_pass retry=3 password sufficient pam_unix.so sha512 shadow nullok try_first_pass use_authtok password sufficient pam_sss.so use_authtok password required pam_deny.so session required pam_mkhomedir.so umask=0022 skel=/etc/skel/ session optional pam_keyinit.so revoke session required pam_limits.so session [success=1 default=ignore] pam_succeed_if.so service in crond quiet use_uid session sufficient pam_sss.so session required pam_unix.so
Need to validate the following para.
authconfig to set up your PAM configuration to use SSSD. Select Use LDAP Authentication, and then replace pam_ldap.so with pam_sss.so in all files below /etc/pam.d or in the /etc/pam.conf file.
include statements in PAM configurations. For example:
... session include system-auth session optional pam_console.so ...
sufficient condition from system-auth returns PAM_SUCCESS, pam_console.so will not be executed.
[domain/<NAME>] sections of the /etc/sssd/sssd.conf file. To enable the Simple Access Provider, you need to set the access_provider parameter to simple, and then add usernames as a comma-separated list to either the simple_allow_users or simple_deny_users parameters.
[sssd] section, and only shows the Simple Access Provider-specific options.
[domain/example.com] access_provider = simple simple_allow_users = user1, user2
simple_allow_users is set, only users from this list are allowed access. This setting supersedes the simple_deny_users list (which would be redundant).
simple_allow_users list is empty, users are allowed access unless they appear in the simple_deny_users list.
simple_allow_users and simple_deny_users are defined.
[domain/<NAME>] sections of the /etc/sssd/sssd.conf file, and listed in order of preference. This list can contain any number of servers.
ldap_uri values:
ldap_uri = ldap://ldap0.mydomain.org, ldap://ldap1.mydomain.org, ldap://ldap2.mydomain.org
ldap://ldap0.mydomain.org functions as the primary server. If this server fails, the SSSD failover mechanism first attempts to connect to ldap1.mydomain.org, and if that is unavailable, it then attempts to connect to ldap2.mydomain.org. If the primary server is restored, the failover mechanism automatically restores operations to use that server instead of any failover servers.
ldap_uri parameters to specify your failover servers. The failover servers must be entered as a comma-separated list of values for a single ldap_uri parameter. If you enter multiple ldap_uri parameters, SSSD only recognizes the last entry.
priority and weight attributes of SRV records provide further opportunity for specifying which servers should be contacted first in the event that the primary server fails.
_service._protocol._domain TTL priority weight port hostname
service._protocol._domain, for example, _ldap._tcp._redhat.com. The client then sorts this list according to the priorities and weights, and connects to the first server in this sorted list.
[sssd] section also lists the services that are active and should be started when sssd starts within the services directive.
NSS — An NSS provider service that answers NSS requests from the nss_sss module.
PAM — A PAM provider service that manages a PAM conversation through the pam_sss PAM module.
monitor — A special service that monitors all other SSSD services, and starts or restarts them as needed. Its options are specified in the [sssd] section of the /etc/sssd/sssd.conf configuration file.
debug_level (integer)
[service/<NAME>] sections in the SSSD configuration file).
reconnection_retries (integer)
DNS lookup fails to return an IPv4 address for a hostname, SSSD attempts to look up an IPv6 address before returning a failure. Note that this only ensures that the async resolver identifies the correct address; there is currently a bug in the LDAP code that prevents SSSD from connecting to an LDAP server over IPv6. This is being investigated separately.
enum_cache_timeout (integer)
entry_cache_nowait_percentage (integer)
entry_cache_timeout value for the domain.
entry_cache_timeout value for each domain.
entry_negative_timeout (integer)
filter_users, filter_groups (string)
root.
filter_users_in_groups (Boolean)
TRUE.
Pluggable Authentication Module (PAM) service.
offline_credentials_expiration (integer)
0 (no limit).
[sssd] section. This example shows only the configuration of Kerberos authentication; it does not include any identity provider.
[domain/FOO] auth_provider = krb5 krb5_kdcip = 192.168.1.1 krb5_realm = EXAMPLE.COM
[domain/<NAME>] sections of the /etc/sssd/sssd.conf file, and then add the list of domains to the domains attribute of the [sssd] section, in the order you want them to be queried.
min_id,max_id (integer)
min_id is unspecified, it defaults to 1000 for any back end.
enumerate (Boolean)
FALSE. Set this value to TRUE to enable enumeration of users and groups of a domain.
timeout (integer)
10 seconds. Raising this timeout might prove useful for slower back ends, such as distant LDAP servers.
timeout = 0, SSSD reverts to the default value; you cannot force a timeout value of zero, because this would force the sssd daemon into a loop.
cache_credentials (Boolean)
FALSE. You should set this value to TRUE for domains other than local if you want to enable offline authentication.
id_provider (string)
NSS provider (for example, nss_nis).
id_provider to proxy, ensure that you also specify a value for proxy_lib_name. Refer to Section 15.1.5.1.2, “Proxy Configuration Options” for information on this attribute.
SSSD internal local provider.
LDAP provider.
entry_cache_timeout (integer)
use_fully_qualified_names (Boolean)
TRUE, all requests to this domain must use fully-qualified domain names. It also means that the output from the request displays the fully-qualified name.
ipauser01, and the use_fully_qualified_names attribute is set to TRUE:
# getent passwd ipauser01[no output]# getent passwd ipauser01@IPAipauser01@IPA:x:937315651:937315651:ipauser01:/home/ipauser01:/bin/sh
use_fully_qualified_names attribute is set to FALSE:
# getent passwd ipauser01ipauser01:x:937315651:937315651:ipauser01:/home/ipauser01:/bin/sh# getent passwd ipauser01@IPAipauser01:x:937315651:937315651:ipauser01:/home/ipauser01:/bin/sh
use_fully_qualified_names set to FALSE, you can continue to use the fully-qualified name in your requests, but only the simplified version is displayed in the output.
name@domain, not name@realm. You can, however, use the same name for both your domain and your realm.
auth_provider (string)
proxy_pam_target (string)
auth_provider option is set to proxy, and specifies the proxy target that PAM proxies to.
/etc/pam.d/ directory.
proxy_lib_name (string)
id_provider option is set to proxy, and specifies which existing NSS library to proxy identity requests through.
nis to use the existing libnss_nis.so file.
/etc/sssd/sssd.conf file.
TLS/SSL is required. If the LDAP server is used only as an identity provider, an encrypted channel is not needed.
/etc/sssd/sssd.conf file to reflect the following example:
# A native LDAP domain [domain/LDAP] enumerate = true cache_credentials = TRUE id_provider = ldap auth_provider = ldap ldap_schema = rfc2307 chpass_provider = ldap ldap_uri = ldap://ldap.mydomain.org ldap_user_search_base = dc=mydomain,dc=org tls_reqcert = demand ldap_tls_cacert = /etc/pki/tls/certs/ca-bundle.crt
ldap_schema attribute can be set to either rfc2307, which uses the memberuid attribute for group membership, or to rfc2307bis, which uses the member attribute. Changes to this setting only affect how SSSD determines the groups to which a user belongs; there is no negative effect on the actual user data. If you do not know the correct value for this attribute, consult your System Administrator.
/etc/sssd/sssd.conf file.
/etc/sssd/sssd.conf file to reflect the following example:
# A domain with identities provided by LDAP and authentication by Kerberos [domain/KRBDOMAIN] enumerate = false id_provider = ldap chpass_provider = krb5 ldap_uri = ldap://ldap.mydomain.org ldap_user_search_base = dc=mydomain,dc=org tls_reqcert = demand ldap_tls_cacert = /etc/pki/tls/certs/ca-bundle.crt auth_provider = krb5 krb5_kdcip = 192.168.1.1 krb5_realm = EXAMPLE.COM krb5_changepw_principle = kadmin/changepw krb5_ccachedir = /tmp krb5_ccname_template = FILE:%d/krb5cc_%U_XXXXXX krb5_auth_timeout = 15
# sss_useradd newUser01
sss_useradd manual page for information on all the options that apply to this command. Also refer to the sss_userdel and sss_usermod manual pages for information on how to delete and modify existing SSSD users.
NSS to use the SSS domain, you can use the following command to request user information:
# getent passwd newUser01@LOCAL
newUser01:x:508:508:newUser01:/home/newUser01:/bin/bash
# passwd newUser01
Changing password for user newUser01.
New password:
Retype new password:
passwd: all authentication tokens updated successfully.
# sss_groupadd newGroup01
sss_groupadd, sss_groupdel, and sss_groupmod manual pages for information on the options that apply to adding, deleting, and modifying SSSD groups.
NSS to use the local sss domain, you can use a simple # getent group command to request information for all groups. The following is an abbreviated display of the output of such a request:
# getent group
root:x:0:root
bin:x:1:root,bin,daemon
daemon:x:2:root,bin,daemon
.
.
.
testuser1:x:500:
testuser2:x:501:
testuser3:x:502:
getent command to view the existing groups and their members:
GroupA:*:511:UserA GroupB:*:512:UserB GroupC:*:516:UserC GroupD:*:517:UserD GroupE:*:518:UserE
sss_groupmod command to add GroupB to GroupA:
# sss_groupmod -a GroupA GroupB
GroupB to GroupA, as can be seen below:
GroupA:*:511:UserA,UserB GroupB:*:512:UserB GroupC:*:516:UserC GroupD:*:517:UserD GroupE:*:518:UserE
GroupA:*:511:UserA,UserB,UserC,UserD,UserE GroupB:*:512:UserB,UserC,UserD,UserE GroupC:*:516:UserC,UserD,UserE GroupD:*:517:UserD,UserE GroupE:*:518:UserE
GroupC from the previous example, the following group and user membership results:
GroupA:*:511:UserA,UserB GroupB:*:512:UserB GroupD:*:517:UserD,UserE GroupE:*:518:UserE
/var/log/sssd/ directory.
/etc/sssd/sssd.conf file), as well as an sssd_pam.log and an sssd_nss.log file. This level of granularity can help you to quickly isolate and resolve any errors or issues you might experience with SSSD.
/var/log/secure file, which logs authentication failures and the reason for the failure. For example, if you see Reason 4: System Error reported against any failure, you should increase the debug level of the log files.
debug_level option in the /etc/sssd/sssd.conf for the domain that is causing concern, and then restart SSSD. Refer to the sssd.conf(5) manual page for more information on how to set the debug_level for a specfic domain.
0 in the /etc/sssd/sssd.conf file:
--debug-timestamps=0
# sssd -d4
[sssd] [ldb] (3): server_sort:Unable to register control with rootdse! [sssd] [confdb_get_domains] (0): No domains configured, fatal error! [sssd] [get_monitor_config] (0): No domains configured.
/etc/sssd/sssd.conf file and ensure you have at least one properly configured domain, and then try to start SSSD.
# sssd -d4
[sssd] [ldb] (3): server_sort:Unable to register control with rootdse! [sssd] [get_monitor_config] (0): No services configured!
/etc/sssd/sssd.conf file and ensure you have at least one available service providers, and then try to start SSSD.
services entry in the /etc/sssd/sssd.conf file. If services are listed in multiple entries, only the last entry is recognized by SSSD.
NSS, their symptoms, and how to resolve them.
NSS fails to return user information
# service sssd status
sssd (pid 21762) is running...
[nss] section of the /etc/sssd/sssd.conf file. For example, ensure that you have not misconfigured the filter_users or filter_groups attributes. Refer to the NSS configuration options section of the sssd.conf(5) manual page for information on how to configure these attributes.
nss in the list of services that sssd should start
/etc/nsswitch.conf file. Refer to the section Section 15.1.3.2.1, “Configuring NSS” for information on how to correctly configure this file.
PAM, their symptoms, and how to resolve them.
[root@clientF11 tmp]# passwd user1000 Changing password for user user1000. New password: Retype new password: New Password: Reenter new Password: passwd: all authentication tokens updated successfully.
use_authtok option is correctly configured in your /etc/pam.d/system-auth file.
use_fully_qualified_domains attribute to TRUE in the /etc/sssd/sssd.conf file.
sssd.conf(5)
sssd-ipa(5)
sssd-krb5(5)
sssd-ldap(5)
sssd(8)
sssd_krb5_locator_plugin(8)
sss_groupadd(8)
sss_groupdel(8)
sss_groupmod(8)
sss_useradd(8)
sss_userdel(8)
sss_usermod(8)
pam_sss(8)
[sssd] config_file_version = 2 services = nss, pam domains = mybox.example.com, ldap.example.com, ipa.example.com, nis.example.com # sbus_timeout = 300 [nss] nss_filter_groups = root nss_filter_users = root nss_entry_cache_timeout = 30 nss_enum_cache_timeout = 30 [domain/mybox.example.com] domain_type = local enumerate = true min_id = 1000 # max_id = 2000 local_default_shell = /bin/bash local_default_homedir = /home # Possible overrides # id_provider = local # auth_provider = local # authz_provider = local # passwd_provider = local [domain/ldap.example.com] domain_type = ldap server = ldap.example.com, ldap3.example.com, 10.0.0.2 # ldap_uri = ldaps://ldap.example.com:9093 # ldap_use_tls = ssl ldap_user_search_base = ou=users,dc=ldap,dc=example,dc=com enumerate = false # Possible overrides # id_provider = ldap # id_server = ldap2.example.com # auth_provider = krb5 # auth_server = krb5.example.com # krb5_realm = KRB5.EXAMPLE.COM [domain/ipa.example.com] domain_type = ipa server = ipa.example.com, ipa2.example.com enumerate = false # Possible overrides # id_provider = ldap # id_server = ldap2.example.com # auth_provider = krb5 # auth_server = krb5.example.com # krb5_realm = KRB5.EXAMPLE.COM [domain/nis.example.com] id_provider = proxy proxy_lib = nis auth_provider = proxy proxy_auth_target = nis_pam_proxy
Table of Contents
/etc/sysconfig/ Directory/etc/sysconfig/arpwatch /etc/sysconfig/authconfig /etc/sysconfig/autofs /etc/sysconfig/clock /etc/sysconfig/desktop /etc/sysconfig/dhcpd /etc/sysconfig/firstboot /etc/sysconfig/i18n /etc/sysconfig/init /etc/sysconfig/ip6tables-config /etc/sysconfig/keyboard /etc/sysconfig/named /etc/sysconfig/network /etc/sysconfig/ntpd /etc/sysconfig/radvd /etc/sysconfig/samba /etc/sysconfig/selinux /etc/sysconfig/sendmail /etc/sysconfig/spamassassin /etc/sysconfig/squid /etc/sysconfig/system-config-users /etc/sysconfig/vncservers /etc/sysconfig/xinetd /etc/sysconfig/ Directoryhalt, poweroff, and reboot.
/etc/inittab specifies that your system is set to shutdown and reboot in response to a Ctrl+Alt+Del key combination used at the console. To completely disable this ability, comment out the following line in /etc/inittab by putting a hash mark (#) in front of it:
ca::ctrlaltdel:/sbin/shutdown -t3 -r now
-a option to the /etc/inittab line shown above, so that it reads:
ca::ctrlaltdel:/sbin/shutdown -a -t3 -r now
-a flag tells shutdown to look for the /etc/shutdown.allow file.
shutdown.allow in /etc. The shutdown.allow file should list the usernames of any users who are allowed to shutdown the system using Ctrl+Alt+Del . The format of the shutdown.allow file is a list of usernames, one per line, like the following:
stephen jack sophie
shutdown.allow file, the users stephen, jack, and sophie are allowed to shutdown the system from the console using Ctrl+Alt+Del . When that key combination is used, the shutdown -a command in /etc/inittab checks to see if any of the users in /etc/shutdown.allow (or root) are logged in on a virtual console. If one of them is, the shutdown of the system continues; if not, an error message is written to the system console instead.
shutdown.allow, refer to the shutdown man page.
rm -f /etc/security/console.apps/*
poweroff, halt, and reboot, which are accessible from the console by default.
rm -f /etc/security/console.apps/poweroffrm -f /etc/security/console.apps/haltrm -f /etc/security/console.apps/reboot
pam_console.so module uses the /etc/security/console.perms file to determine the permissions for users at the system console. The syntax of the file is very flexible; you can edit the file so that these instructions no longer apply. However, the default file has a line that looks like this:
<console>=tty[0-9][0-9]* vc/[0-9][0-9]* :[0-9]\.[0-9] :[0-9]
:0 or mymachine.example.com:1.0, or a device like /dev/ttyS0 or /dev/pts/2. The default is to define that local virtual consoles and local X servers are considered local, but if you want to consider the serial terminal next to you on port /dev/ttyS1 to also be local, you can change that line to read:
<console>=tty[0-9][0-9]* vc/[0-9][0-9]* :[0-9]\.[0-9] :[0-9] /dev/ttyS1
/etc/security/console.perms.d/50-default.perms. To edit file and device permissions, it is advisable to create a new default file in /etc/security/console.perms.d/ containing your preferred settings for a specified set of files or devices. The name of the new default file must begin with a number higher than 50 (for example, 51-default.perms) in order to override 50-default.perms.
51-default.perms in /etc/security/console.perms.d/:
touch /etc/security/console.perms.d/51-default.perms
perms file, 50-default.perms. The first section defines device classes, with lines similar to the following:
<floppy>=/dev/fd[0-1]* \ /dev/floppy/* /mnt/floppy* <sound>=/dev/dsp* /dev/audio* /dev/midi* \ /dev/mixer* /dev/sequencer \ /dev/sound/* /dev/beep \ /dev/snd/* <cdrom>=/dev/cdrom* /dev/cdroms/* /dev/cdwriter* /mnt/cdrom*
<cdrom> refers to the CD-ROM drive. To add a new device, do not define it in the default 50-default.perms file; instead, define it in 51-default.perms. For example, to define a scanner, add the following line to 51-default.perms:
<scanner>=/dev/scanner /dev/usb/scanner*
/dev/scanner is really your scanner and not some other device, such as your hard drive.
/etc/security/console.perms.d/50-default.perms defines this, with lines similar to the following:
<console> 0660 <floppy> 0660 root.floppy <console> 0600 <sound> 0640 root <console> 0600 <cdrom> 0600 root.disk
51-default.perms:
<console> 0600 <scanner> 0600 root
/dev/scanner device with the permissions of 0600 (readable and writable by you only). When you log out, the device is owned by root, and still has the permissions 0600 (now readable and writable by root only).
50-default.perms file. To edit permissions for a device already defined in 50-default.perms, add the desired permission definition for that device in 51-default.perms. This will override whatever permissions are defined in 50-default.perms.
/sbin/ or /usr/sbin/, so the application that you wish to run must be there. After verifying that, perform the following steps:
foo program, to the /usr/bin/consolehelper application:
cd /usr/bin ln -s consolehelper foo
/etc/security/console.apps/foo:
touch /etc/security/console.apps/foo
foo service in /etc/pam.d/. An easy way to do this is to copy the PAM configuration file of the halt service, and then modify the copy if you want to change the behavior:
cp /etc/pam.d/halt /etc/pam.d/foo
/usr/bin/foo is executed, consolehelper is called, which authenticates the user with the help of /usr/sbin/userhelper. To authenticate the user, consolehelper asks for the user's password if /etc/pam.d/foo is a copy of /etc/pam.d/halt (otherwise, it does precisely what is specified in /etc/pam.d/foo ) and then runs /usr/sbin/foo with root permissions.
pam_timestamp and run from the same session is automatically authenticated for the user — the user does not have to enter the root password again.
pam package. To enable this feature, add the following lines to your PAM configuration file in etc/pam.d/:
auth include config-util account include config-util session include config-util
/etc/pam.d/system-config-* configuration files. Note that these lines must be added below any other auth sufficient session optional lines in your PAM configuration file.
pam_timestamp is successfully authenticated from the Applications (the main menu on the panel), the
icon is displayed in the notification area of the panel if you are running the GNOME or KDE desktop environment. After the authentication expires (the default is five minutes), the icon disappears.
floppy Groupfloppy group. Add the user(s) to the floppy group using the tool of your choice. For example, the gpasswd command can be used to add user fred to the floppy group:
gpasswd -a fred floppy
fred is able to access the system's diskette drive from the console.
/etc/sysconfig/ Directory/etc/sysconfig/arpwatch /etc/sysconfig/authconfig /etc/sysconfig/autofs /etc/sysconfig/clock /etc/sysconfig/desktop /etc/sysconfig/dhcpd /etc/sysconfig/firstboot /etc/sysconfig/i18n /etc/sysconfig/init /etc/sysconfig/ip6tables-config /etc/sysconfig/keyboard /etc/sysconfig/named /etc/sysconfig/network /etc/sysconfig/ntpd /etc/sysconfig/radvd /etc/sysconfig/samba /etc/sysconfig/selinux /etc/sysconfig/sendmail /etc/sysconfig/spamassassin /etc/sysconfig/squid /etc/sysconfig/system-config-users /etc/sysconfig/vncservers /etc/sysconfig/xinetd /etc/sysconfig/ Directory/etc/sysconfig/ directory contains a variety of system configuration files for Fedora.
/etc/sysconfig/ directory, their function, and their contents. The information in this chapter is not intended to be complete, as many of these files have a variety of options that are only used in very specific or rare circumstances.
/etc/sysconfig/ Directory/etc/sysconfig/ directory. Files not listed here, as well as extra file options, are found in the /usr/share/doc/initscripts-<version-number>/sysconfig.txt file (replace <version-number> with the version of the initscripts package). Alternatively, looking through the initscripts in the /etc/rc.d/ directory can prove helpful.
/etc/sysconfig/ directory, then the corresponding program may not be installed.
/etc/sysconfig/arpwatch /etc/sysconfig/arpwatch file is used to pass arguments to the arpwatch daemon at boot time. The arpwatch daemon maintains a table of Ethernet MAC addresses and their IP address pairings. By default, this file sets the owner of the arpwatch process to the user pcap and sends any messages to the root mail queue. For more information regarding available parameters for this file, refer to the arpwatch man page.
/etc/sysconfig/authconfig /etc/sysconfig/authconfig file sets the authorization to be used on the host. It contains one or more of the following lines:
USEMD5=<value> , where <value> yes — MD5 is used for authentication.
no — MD5 is not used for authentication.
USEKERBEROS=<value> , where <value> yes — Kerberos is used for authentication.
no — Kerberos is not used for authentication.
USELDAPAUTH=<value> , where <value> yes — LDAP is used for authentication.
no — LDAP is not used for authentication.
/etc/sysconfig/autofs /etc/sysconfig/autofs file defines custom options for the automatic mounting of devices. This file controls the operation of the automount daemons, which automatically mount file systems when you use them and unmount them after a period of inactivity. File systems can include network file systems, CD-ROMs, diskettes, and other media.
/etc/sysconfig/autofs file may contain the following:
LOCALOPTIONS="<value>", where <value> is a string for defining machine-specific automount rules. The default value is an empty string ("").
DAEMONOPTIONS="<value>", where <value> is the timeout length in seconds before unmounting the device. The default value is 60 seconds ("--timeout=60").
UNDERSCORETODOT=<value> , where <value> is a binary value that controls whether to convert underscores in file names into dots. For example, auto_home to auto.home and auto_mnt to auto.mnt. The default value is 1 (true).
DISABLE_DIRECT=<value> , where <value> is a binary value that controls whether to disable direct mount support, as the Linux implementation does not conform to the Sun Microsystems' automounter behavior. The default value is 1 (true), and allows for compatibility with the Sun automounter options specification syntax.
/etc/sysconfig/clock /etc/sysconfig/clock file controls the interpretation of values read from the system hardware clock.
UTC=<value> , where <value> true or yes — The hardware clock is set to Universal Time.
false or no — The hardware clock is set to local time.
ARC=<value> , where <value> false or no — This value indicates that the normal UNIX epoch is in use. Other values are used by systems not supported by Fedora.
SRM=<value> , where <value> false or no — This value indicates that the normal UNIX epoch is in use. Other values are used by systems not supported by Fedora.
ZONE=<filename> — The time zone file under /usr/share/zoneinfo that /etc/localtime is a copy of. The file contains information such as:
ZONE="America/New York"
ZONE parameter is read by the Time and Date Properties Tool (system-config-date), and manually editing it does not change the system timezone.
CLOCKMODE=<value> , where <value> GMT — The clock is set to Universal Time (Greenwich Mean Time).
ARC — The ARC console's 42-year time offset is in effect (for Alpha-based systems only).
/etc/sysconfig/desktop /etc/sysconfig/desktop file specifies the desktop for new users and the display manager to run when entering runlevel 5.
DESKTOP="<value>", where "<value>" is one of the following:
GNOME — Selects the GNOME desktop environment.
KDE — Selects the KDE desktop environment.
DISPLAYMANAGER="<value>", where "<value>" is one of the following:
GNOME — Selects the GNOME Display Manager.
KDE — Selects the KDE Display Manager.
XDM — Selects the X Display Manager.
/etc/sysconfig/dhcpd /etc/sysconfig/dhcpd file is used to pass arguments to the dhcpd daemon at boot time. The dhcpd daemon implements the Dynamic Host Configuration Protocol (DHCP) and the Internet Bootstrap Protocol (BOOTP). DHCP and BOOTP assign hostnames to machines on the network. For more information about what parameters are available in this file, refer to the dhcpd man page.
/etc/sysconfig/firstboot /sbin/init program calls the etc/rc.d/init.d/firstboot script, which in turn launches the Setup Agent. This application allows the user to install the latest updates as well as additional applications and documentation.
/etc/sysconfig/firstboot file tells the Setup Agent application not to run on subsequent reboots. To run it the next time the system boots, remove /etc/sysconfig/firstboot and execute chkconfig --level 5 firstboot on.
/etc/sysconfig/i18n /etc/sysconfig/i18n file sets the default language, any supported languages, and the default system font. For example:
LANG="en_US.UTF-8" SUPPORTED="en_US.UTF-8:en_US:en" SYSFONT="latarcyrheb-sun16"
/etc/sysconfig/init /etc/sysconfig/init file controls how the system appears and functions during the boot process.
BOOTUP=<value> , where <value> color — The standard color boot display, where the success or failure of devices and services starting up is shown in different colors.
verbose — An old style display which provides more information than purely a message of success or failure.
RES_COL=<value> , where <value> MOVE_TO_COL=<value> , where <value> RES_COL line via the echo -en command.
SETCOLOR_SUCCESS=<value> , where <value> echo -en command. The default color is set to green.
SETCOLOR_FAILURE=<value> , where <value> echo -en command. The default color is set to red.
SETCOLOR_WARNING=<value> , where <value> echo -en command. The default color is set to yellow.
SETCOLOR_NORMAL=<value> , where <value> echo -en.
LOGLEVEL=<value> , where <value> syslogd daemon overrides this setting once started.
PROMPT=<value> , where <value> yes — Enables the key check for interactive mode.
no — Disables the key check for interactive mode.
/etc/sysconfig/ip6tables-config /etc/sysconfig/ip6tables-config file stores information used by the kernel to set up IPv6 packet filtering at boot time or whenever the ip6tables service is started.
ip6tables rules. Rules also can be created manually using the /sbin/ip6tables command. Once created, add the rules to the /etc/sysconfig/ip6tables file by typing the following command:
/sbin/service ip6tables save
ip6tables, refer to .
/etc/sysconfig/keyboard /etc/sysconfig/keyboard file controls the behavior of the keyboard. The following values may be used:
KEYBOARDTYPE="sun|pc" where sun means a Sun keyboard is attached on /dev/kbd, or pc means a PS/2 keyboard connected to a PS/2 port.
KEYTABLE="<file>", where <file> KEYTABLE="us". The files that can be used as keytables start in /lib/kbd/keymaps/i386 and branch into different keyboard layouts from there, all labeled <file>.kmap.gz/lib/kbd/keymaps/i386 that matches the KEYTABLE setting is used.
/etc/sysconfig/named /etc/sysconfig/named file is used to pass arguments to the named daemon at boot time. The named daemon is a Domain Name System (DNS) server which implements the Berkeley Internet Name Domain (BIND) version 9 distribution. This server maintains a table of which hostnames are associated with IP addresses on the network.
ROOTDIR="</some/where>" , where </some/where> named runs. This chroot environment must first be configured. Type info chroot for more information.
OPTIONS="<value>" , where <value> named except -t. In place of -t, use the ROOTDIR line above.
named man page. For detailed information on how to configure a BIND DNS server, refer to Chapter 7, The BIND DNS Server. By default, the file contains no parameters.
/etc/sysconfig/network /etc/sysconfig/network file is used to specify information about the desired network configuration. The following values may be used:
NETWORKING=<value> , where <value> yes — Networking should be configured.
no — Networking should not be configured.
HOSTNAME=<value> , where <value> hostname.expample.com, but can be whatever hostname is necessary.
GATEWAY=<value> , where <value> GATEWAYDEV=<value> , where <value> eth0. Configure this option if you have multiple interfaces on the same subnet, and require one of those interfaces to be the preferred route to the default gateway.
NISDOMAIN=<value> , where <value> NOZEROCONF=<value> , where setting <value> true disables the zeroconf route.
/etc/sysconfig/ntpd /etc/sysconfig/ntpd file is used to pass arguments to the ntpd daemon at boot time. The ntpd daemon sets and maintains the system clock to synchronize with an Internet standard time server. It implements version 4 of the Network Time Protocol (NTP). For more information about what parameters are available for this file, use a Web browser to view the following file: /usr/share/doc/ntp-<version>/ntpd.htm (where <version> is the version number of ntpd). By default, this file sets the owner of the ntpd process to the user ntp.
/etc/sysconfig/radvd /etc/sysconfig/radvd file is used to pass arguments to the radvd daemon at boot time. The radvd daemon listens for router requests and sends router advertisements for the IP version 6 protocol. This service allows hosts on a network to dynamically change their default routers based on these router advertisements. For more information about available parameters for this file, refer to the radvd man page. By default, this file sets the owner of the radvd process to the user radvd.
/etc/sysconfig/samba /etc/sysconfig/samba file is used to pass arguments to the smbd and the nmbd daemons at boot time. The smbd daemon offers file sharing connectivity for Windows clients on the network. The nmbd daemon offers NetBIOS over IP naming services. For more information about what parameters are available for this file, refer to the smbd man page. By default, this file sets smbd and nmbd to run in daemon mode.
/etc/sysconfig/selinux /etc/sysconfig/selinux file contains the basic configuration options for SELinux. This file is a symbolic link to /etc/selinux/config.
/etc/sysconfig/sendmail /etc/sysconfig/sendmail file allows messages to be sent to one or more clients, routing the messages over whatever networks are necessary. The file sets the default values for the Sendmail application to run. Its default values are set to run as a background daemon and to check its queue each hour in case something has backed up.
DAEMON=<value> , where <value> yes — Sendmail should be configured to listen to port 25 for incoming mail. yes implies the use of Sendmail's -bd options.
no — Sendmail should not be configured to listen to port 25 for incoming mail.
QUEUE=1h which is given to Sendmail as -q$QUEUE. The -q option is not given to Sendmail if /etc/sysconfig/sendmail exists and QUEUE is empty or undefined.
/etc/sysconfig/spamassassin /etc/sysconfig/spamassassin file is used to pass arguments to the spamd daemon (a daemonized version of Spamassassin) at boot time. Spamassassin is an email spam filter application. For a list of available options, refer to the spamd man page. By default, it configures spamd to run in daemon mode, create user preferences, and auto-create whitelists (allowed bulk senders).
/etc/sysconfig/squid /etc/sysconfig/squid file is used to pass arguments to the squid daemon at boot time. The squid daemon is a proxy caching server for Web client applications. For more information on configuring a squid proxy server, use a Web browser to open the /usr/share/doc/squid-<version>/ directory (replace <version> with the squid version number installed on the system). By default, this file sets squid to start in daemon mode and sets the amount of time before it shuts itself down.
/etc/sysconfig/system-config-users /etc/sysconfig/system-config-users file is the configuration file for the graphical application, User Manager. This file is used to filter out system users such as root, daemon, or lp. This file is edited by the > pull-down menu in the User Manager application and should never be edited by hand. For more information on using this application, refer to Section 21.1, “User and Group Configuration”.
/etc/sysconfig/vncservers /etc/sysconfig/vncservers file configures the way the Virtual Network Computing (VNC) server starts up.
VNCSERVERS=<value> , where <value> "1:fred", to indicate that a VNC server should be started for user fred on display :1. User fred must have set a VNC password using the vncpasswd command before attempting to connect to the remote VNC server.
/etc/sysconfig/xinetd /etc/sysconfig/xinetd file is used to pass arguments to the xinetd daemon at boot time. The xinetd daemon starts programs that provide Internet services when a request to the port for that service is received. For more information about available parameters for this file, refer to the xinetd man page. For more information on the xinetd service, refer to .
/etc/sysconfig/ Directory/etc/sysconfig/.
apm-scripts/ /etc/sysconfig/apm-scripts/apmcontinue which is called at the end of the script. It is also possible to control the script by editing /etc/sysconfig/apmd.
cbq/ networking/ system-config-network), and its contents should not be edited manually. For more information about configuring network interfaces using the Network Administration Tool, refer to Chapter 5, Network Configuration.
network-scripts/ ifcfg-eth0 for the eth0 Ethernet interface.
ifup and ifdown.
ifup-isdn and ifdown-isdn.
network-scripts directory, refer to Chapter 4, Network Interfaces.
rhn/ /etc/sysconfig/ directory. The following source contains more comprehensive information.
/usr/share/doc/initscripts-<version-number>/sysconfig.txt — This file contains a more authoritative listing of the files found in the /etc/sysconfig/ directory and the configuration options available for them. The <version-number> in the path to this file corresponds to the version of the initscripts package installed.
system-config-date, system-config-time, or dateconfig at a shell prompt (for example, in an XTerm or a GNOME terminal).
system-config-keyboard at a shell prompt.
Xorg binary) listens for connections from X client applications via a network or local loopback interface. The server communicates with the hardware, such as the video card, monitor, keyboard, and mouse. X client applications exist in the user-space, creating a graphical user interface (GUI) for the user and passing user requests to the X server.
/usr/ instead of /usr/X11R6. The /etc/X11/ directory contains configuration files for X client and server applications. This includes configuration files for the X server itself, the xfs font server, the X display managers, and many other base components.
/etc/fonts/fonts.conf. For more on configuring and adding fonts, refer to Section 20.4, “Fonts”.
/etc/X11/xorg.conf. For information about the structure of this file, refer to Section 20.3, “X Server Configuration Files”.
kwin metacity metacity package.
mwm mwm) is a basic, stand-alone window manager. Since it is designed to be a stand-alone window manager, it should not be used in conjunction with GNOME or KDE. To run this window manager, you need to install the openmotif package.
twm twm, which provides the most basic tool set of any of the window managers, can be used either as a stand-alone or with a desktop environment. It is installed as part of the X11R7.1 release.
xinit -e <path-to-window-manager> at the prompt.
<path-to-window-manager> is the location of the window manager binary file. The binary file can be located by typing which window-manager-name , where window-manager-name user@host#which twm/usr/bin/twmuser@host#xinit -e /usr/bin/twm
twm window manager, the second command starts twm.
startx at the prompt.
/usr/bin/Xorg). Associated configuration files are stored in the /etc/X11/ directory (as is a symbolic link — X — which points to /usr/bin/Xorg). The configuration file for the X server is /etc/X11/xorg.conf.
/usr/lib/xorg/modules/ contains X server modules that can be loaded dynamically at runtime. By default, only some modules in /usr/lib/xorg/modules/ are automatically loaded by the X server.
/etc/X11/xorg.conf. For more information about loading modules, refer to Section 20.3.1.5, “ Module ”.
xorg.conf /etc/X11/xorg.conf file, it is useful to understand the various sections and optional parameters available, especially when troubleshooting.
/etc/X11/xorg.conf file is comprised of many different sections which address specific aspects of the system hardware.
Section "<section-name>" line (where <section-name> is the title for the section) and ends with an EndSection line. Each section contains lines that include option names and one or more option values. These are sometimes enclosed in double quotes (").
#) are not read by the X server and are used for human-readable comments.
/etc/X11/xorg.conf file accept a boolean switch which turns the feature on or off. Acceptable boolean values are:
1, on, true, or yes — Turns the option on.
0, off, false, or no — Turns the option off.
/etc/X11/xorg.conf file. More detailed information about the X server configuration file can be found in the xorg.conf man page.
ServerFlags ServerFlags section contains miscellaneous global X server settings. Any settings in this section may be overridden by options placed in the ServerLayout section (refer to Section 20.3.1.3, “ ServerLayout ” for details).
ServerFlags section is on its own line and begins with the term Option followed by an option enclosed in double quotation marks (").
ServerFlags section:
Section "ServerFlags" Option "DontZap" "true" EndSection
"DontZap" "<boolean>" — When the value of <boolean> is set to true, this setting prevents the use of the Ctrl+Alt+Backspace key combination to immediately terminate the X server.
"DontZoom" "<boolean>" — When the value of <boolean> is set to true, this setting prevents cycling through configured video resolutions using the Ctrl+Alt+Keypad-Plus and Ctrl+Alt+Keypad-Minus key combinations.
ServerLayout ServerLayout section binds together the input and output devices controlled by the X server. At a minimum, this section must specify one output device and one input device. By default, a monitor (output device) and keyboard (input device) are specified.
ServerLayout section:
Section "ServerLayout" Identifier "Default Layout" Screen 0 "Screen0" 0 0 InputDevice "Mouse0" "CorePointer" InputDevice "Keyboard0" "CoreKeyboard" EndSection
ServerLayout section:
Identifier — Specifies a unique name for this ServerLayout section.
Screen — Specifies the name of a Screen section to be used with the X server. More than one Screen option may be present.
Screen entry:
Screen 0 "Screen0" 0 0
Screen entry (0) indicates that the first monitor connector or head on the video card uses the configuration specified in the Screen section with the identifier "Screen0".
Screen section with the identifier "Screen0" can be found in Section 20.3.1.9, “ Screen ”.
Screen entry with a different number and a different Screen section identifier is necessary .
"Screen0" give the absolute X and Y coordinates for the upper-left corner of the screen (0 0 by default).
InputDevice — Specifies the name of an InputDevice section to be used with the X server.
InputDevice entries: one for the default mouse and one for the default keyboard. The options CorePointer and CoreKeyboard indicate that these are the primary mouse and keyboard.
Option "<option-name>" — An optional entry which specifies extra parameters for the section. Any options listed here override those listed in the ServerFlags section.
<option-name> with a valid option listed for this section in the xorg.conf man page.
ServerLayout section in the /etc/X11/xorg.conf file. By default, the server only reads the first one it encounters, however.
ServerLayout section, it can be specified as a command line argument when starting an X session.
Files Files section sets paths for services vital to the X server, such as the font path. This is an optional section, these paths are normally detected automatically. This section may be used to override any automatically detected defaults.
Files section:
Section "Files" RgbPath "/usr/share/X11/rgb.txt" FontPath "unix/:7100" EndSection
Files section:
RgbPath — Specifies the location of the RGB color database. This database defines all valid color names in X and ties them to specific RGB values.
FontPath — Specifies where the X server must connect to obtain fonts from the xfs font server.
FontPath is unix/:7100. This tells the X server to obtain font information using UNIX-domain sockets for inter-process communication (IPC) on port 7100.
ModulePath — An optional parameter which specifies alternate directories which store X server modules.
Module /usr/lib/xorg/modules/ directory:
extmod
dbe
glx
freetype
type1
record
dri
ModulePath parameter in the Files section. Refer to Section 20.3.1.4, “ Files ” for more information on this section.
Module section to /etc/X11/xorg.conf instructs the X server to load the modules listed in this section instead of the default modules.
Module section:
Section "Module" Load "fbdevhw" EndSection
fbdevhw instead of the default modules.
Module section to /etc/X11/xorg.conf, you will need to specify any default modules you want to load as well as any extra modules.
InputDevice InputDevice section configures one input device for the X server. Systems typically have at least one InputDevice section for the keyboard. It is perfectly normal to have no entry for a mouse, as most mouse settings are automatically detected.
InputDevice section for a keyboard:
Section "InputDevice" Identifier "Keyboard0" Driver "kbd" Option "XkbModel" "pc105" Option "XkbLayout" "us" EndSection
InputDevice section:
Identifier — Specifies a unique name for this InputDevice section. This is a required entry.
Driver — Specifies the name of the device driver X must load for the device.
Option — Specifies necessary options pertaining to the device.
xorg.conf:
Protocol — Specifies the protocol used by the mouse, such as IMPS/2.
Device — Specifies the location of the physical device.
Emulate3Buttons — Specifies whether to allow a two-button mouse to act like a three-button mouse when both mouse buttons are pressed simultaneously.
xorg.conf man page for a list of valid options for this section.
Monitor Monitor section configures one type of monitor used by the system. This is an optional entry as well, as most monitors are now automatically detected.
Monitor section for a monitor:
Section "Monitor" Identifier "Monitor0" VendorName "Monitor Vendor" ModelName "DDC Probed Monitor - ViewSonic G773-2" DisplaySize 320 240 HorizSync 30.0 - 70.0 VertRefresh 50.0 - 180.0 EndSection
Monitor section of /etc/X11/xorg.conf. Inappropriate values can damage or destroy a monitor. Consult the monitor's documentation for a listing of safe operating parameters.
Monitor section:
Identifier — Specifies a unique name for this Monitor section. This is a required entry.
VendorName — An optional parameter which specifies the vendor of the monitor.
ModelName — An optional parameter which specifies the monitor's model name.
DisplaySize — An optional parameter which specifies, in millimeters, the physical size of the monitor's picture area.
HorizSync — Specifies the range of horizontal sync frequencies compatible with the monitor in kHz. These values help the X server determine the validity of built-in or specified Modeline entries for the monitor.
VertRefresh — Specifies the range of vertical refresh frequencies supported by the monitor, in kHz. These values help the X server determine the validity of built in or specified Modeline entries for the monitor.
Modeline — An optional parameter which specifies additional video modes for the monitor at particular resolutions, with certain horizontal sync and vertical refresh resolutions. Refer to the xorg.conf man page for a more detailed explanation of Modeline entries.
Option "<option-name>" — An optional entry which specifies extra parameters for the section. Replace <option-name> with a valid option listed for this section in the xorg.conf man page.
Device Device section configures one video card on the system. While one Device section is the minimum, additional instances may occur for each video card installed on the machine.
Device section for a video card:
Section "Device" Identifier "Videocard0" Driver "mga" VendorName "Videocard vendor" BoardName "Matrox Millennium G200" VideoRam 8192 Option "dpms" EndSection
Device section:
Identifier — Specifies a unique name for this Device section. This is a required entry.
Driver — Specifies which driver the X server must load to utilize the video card. A list of drivers can be found in /usr/share/hwdata/videodrivers, which is installed with the hwdata package.
VendorName — An optional parameter which specifies the vendor of the video card.
BoardName — An optional parameter which specifies the name of the video card.
VideoRam — An optional parameter which specifies the amount of RAM available on the video card in kilobytes. This setting is only necessary for video cards the X server cannot probe to detect the amount of video RAM.
BusID — An entry which specifies the bus location of the video card. On systems with only one video card a BusID entry is optional and may not even be present in the default /etc/X11/xorg.conf file. On systems with more than one video card, however, a BusID entry must be present.
Screen — An optional entry which specifies which monitor connector or head on the video card the Device section configures. This option is only useful for video cards with multiple heads.
Device sections must exist and each of these sections must have a different Screen value.
Screen entry must be an integer. The first head on the video card has a value of 0. The value for each additional head increments this value by one.
Option "<option-name>" — An optional entry which specifies extra parameters for the section. Replace <option-name> with a valid option listed for this section in the xorg.conf man page.
"dpms" (for Display Power Management Signaling, a VESA standard), which activates the Service Star energy compliance setting for the monitor.
Screen Screen section binds one video card (or video card head) to one monitor by referencing the Device section and the Monitor section for each. While one Screen section is the minimum, additional instances may occur for each video card and monitor combination present on the machine.
Screen section:
Section "Screen" Identifier "Screen0" Device "Videocard0" Monitor "Monitor0" DefaultDepth 16 SubSection "Display" Depth 24 Modes "1280x1024" "1280x960" "1152x864" "1024x768" "800x600" "640x480" EndSubSection SubSection "Display" Depth 16 Modes "1152x864" "1024x768" "800x600" "640x480" EndSubSection EndSection
Screen section:
Identifier — Specifies a unique name for this Screen section. This is a required entry.
Device — Specifies the unique name of a Device section. This is a required entry.
Monitor — Specifies the unique name of a Monitor section. This is only required if a specific Monitor section is defined in the xorg.conf file. Normally, monitors are automatically detected.
DefaultDepth — Specifies the default color depth in bits. In the previous example, 16 (which provides thousands of colors) is the default. Only one DefaultDepth is permitted, although this can be overridden with the Xorg command line option -depth <n> ,where <n> SubSection "Display" — Specifies the screen modes available at a particular color depth. The Screen section can have multiple Display subsections, which are entirely optional since screen modes are automatically detected.
Option "<option-name>" — An optional entry which specifies extra parameters for the section. Replace <option-name> with a valid option listed for this section in the xorg.conf man page.
DRI DRI section specifies parameters for the Direct Rendering Infrastructure (DRI). DRI is an interface which allows 3D software applications to take advantage of 3D hardware acceleration capabilities built into most modern video hardware. In addition, DRI can improve 2D performance via hardware acceleration, if supported by the video card driver.
xorg.conf file will override those defaults.
DRI section:
Section "DRI" Group 0 Mode 0666 EndSection
xfs.
/etc/fonts/fonts.conf configuration file, which should not be edited by hand.
~/.gtkrc.mine:
style "user-font" { fontset = "<font-specification>" } widget_class "*" style "user-font"
<font-specification> with a font specification in the style used by traditional X applications, such as -adobe-helvetica-medium-r-normal--*-120-*-*-*-*-*-*. A full list of core fonts can be obtained by running xlsfonts or created interactively using the xfontsel command.
/usr/share/fonts/ directory. It is a good idea to create a new subdirectory, such as local/ or similar, to help distinguish between user-installed and default fonts.
.fonts/ directory in the user's home directory.
fc-cache command to update the font information cache, as in the following example:
fc-cache <path-to-font-directory>
<path-to-font-directory> with the directory containing the new fonts (either /usr/share/fonts/local/ or /home/<user>/.fonts/).
fonts:/// into the Nautilus address bar, and dragging the new font files there.
.gz extension, it is compressed and cannot be used until uncompressed. To do this, use the gunzip command or double-click the file and drag the font to a directory in Nautilus.
xfs) to provide fonts to X client applications.
FontPath directive within the Files section of the /etc/X11/xorg.conf configuration file. Refer to Section 20.3.1.4, “ Files ” for more information about the FontPath entry.
xfs server on a specified port to acquire font information. For this reason, the xfs service must be running for X to start. For more about configuring services for a particular runlevel, refer to Chapter 6, Controlling Access to Services.
xfs Configuration/etc/rc.d/init.d/xfs script starts the xfs server. Several options can be configured within its configuration file, /etc/X11/fs/config.
alternate-servers — Specifies a list of alternate font servers to be used if this font server is not available. A comma must separate each font server in a list.
catalogue — Specifies an ordered list of font paths to use. A comma must separate each font path in a list.
:unscaled immediately after the font path to make the unscaled fonts in that path load first. Then specify the entire path again, so that other scaled fonts are also loaded.
client-limit — Specifies the maximum number of clients the font server services. The default is 10.
clone-self — Allows the font server to clone a new version of itself when the client-limit is hit. By default, this option is on.
default-point-size — Specifies the default point size for any font that does not specify this value. The value for this option is set in decipoints. The default of 120 corresponds to a 12 point font.
default-resolutions — Specifies a list of resolutions supported by the X server. Each resolution in the list must be separated by a comma.
deferglyphs — Specifies whether to defer loading glyphs (the graphic used to visually represent a font). To disable this feature use none, to enable this feature for all fonts use all, or to turn this feature on only for 16-bit fonts use 16.
error-file — Specifies the path and file name of a location where xfs errors are logged.
no-listen — Prevents xfs from listening to particular protocols. By default, this option is set to tcp to prevent xfs from listening on TCP ports for security reasons.
xfs is used to serve fonts over the network, remove this line.
port — Specifies the TCP port that xfs listens on if no-listen does not exist or is commented out.
use-syslog — Specifies whether to use the system error log.
xfs xfs), follow these steps:
/usr/share/fonts/local/ using the following command as root:
mkdir /usr/share/fonts/local/
/usr/share/fonts/local/ directory is necessary, it must be added to the xfs path using the following command as root:
chkfontpath --add /usr/share/fonts/local/
/usr/share/fonts/local/ directory
ttmkfdir -d /usr/share/fonts/local/ -o /usr/share/fonts/local/fonts.scale
xfs font server configuration file by issuing the following command as root:
service xfs reload
startx. The startx command is a front-end to the xinit command, which launches the X server (Xorg) and connects X client applications to it. Because the user is already logged into the system at runlevel 3, startx does not launch a display manager or authenticate users. Refer to Section 20.5.2, “Runlevel 5” for more information about display managers.
startx command is executed, it searches for the .xinitrc file in the user's home directory to define the desktop environment and possibly other X client applications to run. If no .xinitrc file is present, it uses the system default /etc/X11/xinit/xinitrc file instead.
xinitrc script then searches for user-defined files and default system files, including .Xresources, .Xmodmap, and .Xkbmap in the user's home directory, and Xresources, Xmodmap, and Xkbmap in the /etc/X11/ directory. The Xmodmap and Xkbmap files, if they exist, are used by the xmodmap utility to configure the keyboard. The Xresources file is read to assign specific preference values to applications.
xinitrc script executes all scripts located in the /etc/X11/xinit/xinitrc.d/ directory. One important script in this directory is xinput.sh, which configures settings such as the default language.
xinitrc script attempts to execute .Xclients in the user's home directory and turns to /etc/X11/xinit/Xclients if it cannot be found. The purpose of the Xclients file is to start the desktop environment or, possibly, just a basic window manager. The .Xclients script in the user's home directory starts the user-specified desktop environment in the .Xclients-default file. If .Xclients does not exist in the user's home directory, the standard /etc/X11/xinit/Xclients script attempts to start another desktop environment, trying GNOME first and then KDE followed by twm.
GNOME — The default display manager for Fedora, GNOME allows the user to configure language settings, shutdown, restart or log in to the system.
KDE — KDE's display manager which allows the user to shutdown, restart or log in to the system.
xdm — A very basic display manager which only lets the user log in to the system.
prefdm script determines the preferred display manager by referencing the /etc/sysconfig/desktop file. A list of options for this file is available in this file:
/usr/share/doc/initscripts-<version-number>/sysconfig.txt
<version-number> is the version number of the initscripts package.
/etc/X11/xdm/Xsetup_0 file to set up the login screen. Once the user logs into the system, the /etc/X11/xdm/GiveConsole script runs to assign ownership of the console to the user. Then, the /etc/X11/xdm/Xsession script runs to accomplish many of the tasks normally performed by the xinitrc script when starting X from runlevel 3, including setting system and user resources, as well as running the scripts in the /etc/X11/xinit/xinitrc.d/ directory.
GNOME or KDE display managers by selecting it from the menu item (accessed by selecting System (on the panel) > > > ). If the desktop environment is not specified in the display manager, the /etc/X11/xdm/Xsession script checks the .xsession and .Xclients files in the user's home directory to decide which desktop environment to load. As a last resort, the /etc/X11/xinit/Xclients file is used to select a desktop environment or window manager to use in the same way as runlevel 3.
:0) and logs out, the /etc/X11/xdm/TakeConsole script runs and reassigns ownership of the console to the root user. The original display manager, which continues running after the user logged in, takes control by spawning a new display manager. This restarts the X server, displays a new login window, and starts the entire process over again.
/usr/share/doc/gdm-<version-number>/README (where <version-number> is the version number for the gdm package installed) and the xdm man page.
/usr/share/X11/doc/ — contains detailed documentation on the X Window System architecture, as well as how to get additional information about the Xorg project as a new user.
man xorg.conf — Contains information about the xorg.conf configuration files, including the meaning and syntax for the different sections within the files.
man Xorg — Describes the Xorg display server.
system-config-users at the shell prompt to open the User Manager. Viewing and modifying user and group information requires superuser privileges. If you are not the superuser when you open the User Manager, it will prompt you for the superuser password.
/bin/bash. The default home directory is /home/<username>/. You can change the home directory that is created for the user, or you can choose not to create the home directory by unselecting Create home directory.
/etc/skel/ directory into the new home directory.
system-config-users). For more information on User Manager, refer to Section 21.1, “User and Group Configuration”.
useradd, usermod, and userdel — Industry-standard methods of adding, deleting and modifying user accounts
groupadd, groupmod, and groupdel — Industry-standard methods of adding, deleting, and modifying user groups
gpasswd — Industry-standard method of administering the /etc/group file
pwck, grpck — Tools used for the verification of the password, group, and associated shadow files
pwconv, pwunconv — Tools used for the conversion of passwords to shadow passwords and back to standard passwords
useradd are detailed in Table 21.1, “ useradd Command Line Options”.
| Option | Description |
|---|---|
-c '<comment>'
|
<comment> can be replaced with any string. This option is generally used to specify the full name of a user.
|
-d <home-dir>
|
Home directory to be used instead of default /home/
|
-e <date>
| Date for the account to be disabled in the format YYYY-MM-DD |
-f <days>
|
Number of days after the password expires until the account is disabled. If 0 is specified, the account is disabled immediately after the password expires. If -1 is specified, the account is not be disabled after the password expires.
|
-g <group-name>
| Group name or group number for the user's default group. The group must exist prior to being specified here. |
-G <group-list>
| List of additional (other than default) group names or group numbers, separated by commas, of which the user is a member. The groups must exist prior to being specified here. |
-m
| Create the home directory if it does not exist. |
-M
| Do not create the home directory. |
-n
| Do not create a user private group for the user. |
-r
| Create a system account with a UID less than 500 and without a home directory |
-p <password>
|
The password encrypted with crypt
|
-s
|
User's login shell, which defaults to /bin/bash
|
-u <uid>
| User ID for the user, which must be unique and greater than 499 |
useradd Command Line Optionsgroupadd:
groupadd <group-name>
groupadd are detailed in Table 21.2, “ groupadd Command Line Options”.
| Option | Description |
|---|---|
-g <gid>
| Group ID for the group, which must be unique and greater than 499 |
-r
| Create a system group with a GID less than 500 |
-f
|
When used with -g <gid> and <gid> already exists, groupadd will choose another unique <gid> for the group.
|
groupadd Command Line Optionschage command, followed by an option from Table 21.3, “ chage Command Line Options”, followed by the username of the user.
chage command.
| Option | Description |
|---|---|
-m <days>
| Specifies the minimum number of days between which the user must change passwords. If the value is 0, the password does not expire. |
-M <days>
|
Specifies the maximum number of days for which the password is valid. When the number of days specified by this option plus the number of days specified with the -d option is less than the current day, the user must change passwords before using the account.
|
-d <days>
| Specifies the number of days since January 1, 1970 the password was changed |
-I <days>
| Specifies the number of inactive days after the password expiration before locking the account. If the value is 0, the account is not locked after the password expires. |
-E <date>
| Specifies the date on which the account is locked, in the format YYYY-MM-DD. Instead of the date, the number of days since January 1, 1970 can also be used. |
-W <days>
| Specifies the number of days before the password expiration date to warn the user. |
chage Command Line Optionschage command is followed directly by a username (with no options), it displays the current password aging values and allows them to be changed.
useradd command to create the user account, but do not give it a password so that it remains locked.
usermod -L username
chage -d 0 username
passwd command to set the password as it disables the immediate password expiration just configured.
python command. It displays the following:
Python 2.4.3 (#1, Jul 21 2006, 08:46:09) [GCC 4.1.1 20060718 (Red Hat 4.1.1-9)] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>>
<password> with the password to encrypt and <salt> with a random combination of at least 2 of the following: any alphanumeric character, the slash (/) character or a dot (.):
import crypt; print crypt.crypt("<password>","<salt>")
'12CsGd8FRcMSM'.
<encrypted-password> with the encrypted output of the Python interpreter):
usermod -p "<encrypted-password>"<username>
usermod -p "" username
useradd juan is issued on a system that has shadow passwords enabled:
juan is created in /etc/passwd. The line has the following characteristics:
juan.
x for the password field indicating that the system is using shadow passwords.
juan is set to /home/juan/.
/bin/bash.
juan is created in /etc/shadow. The line has the following characteristics:
juan.
!!) appear in the password field of the /etc/shadow file, which locks the account.
-p flag, it is placed in the /etc/shadow file on the new line for the user.
juan is created in /etc/group. A group with the same name as a user is called a user private group. For more information on user private groups, refer to Section 21.1.1, “Adding a New User”.
/etc/group has the following characteristics:
juan.
x appears in the password field indicating that the system is using shadow group passwords.
juan in /etc/passwd.
juan is created in /etc/gshadow. The line has the following characteristics:
juan.
!) appears in the password field of the /etc/gshadow file, which locks the group.
juan is created in the /home/ directory. This directory is owned by user juan and group juan. However, it has read, write, and execute privileges only for the user juan. All other permissions are denied.
/etc/skel/ directory (which contain default user settings) are copied into the new /home/juan/ directory.
juan exists on the system. To activate it, the administrator must next assign a password to the account using the passwd command and, optionally, set password aging guidelines.
/etc/passwd file by an Everything installation. The groupid (GID) in this table is the primary group for the user. See Section 21.4, “Standard Groups” for a listing of standard groups.
| User | UID | GID | Home Directory | Shell |
|---|---|---|---|---|
| root | 0 | 0 |
/root
|
/bin/bash
|
| bin | 1 | 1 |
/bin
|
/sbin/nologin
|
| daemon | 2 | 2 |
/sbin
|
/sbin/nologin
|
| adm | 3 | 4 |
/var/adm
|
/sbin/nologin
|
| lp | 4 | 7 |
/var/spool/lpd
|
/sbin/nologin
|
| sync | 5 | 0 |
/sbin
|
/bin/sync
|
| shutdown | 6 | 0 |
/sbin
|
/sbin/shutdown
|
| halt | 7 | 0 |
/sbin
|
/sbin/halt
|
| 8 | 12 |
/var/spool/mail
|
/sbin/nologin
| |
| news | 9 | 13 |
/etc/news
| |
| uucp | 10 | 14 |
/var/spool/uucp
|
/sbin/nologin
|
| operator | 11 | 0 |
/root
|
/sbin/nologin
|
| games | 12 | 100 |
/usr/games
|
/sbin/nologin
|
| gopher | 13 | 30 |
/var/gopher
|
/sbin/nologin
|
| ftp | 14 | 50 |
/var/ftp
|
/sbin/nologin
|
| nobody | 99 | 99 |
/
|
/sbin/nologin
|
| rpm | 37 | 37 |
/var/lib/rpm
|
/sbin/nologin
|
| vcsa | 69 | 69 |
/dev
|
/sbin/nologin
|
| dbus | 81 | 81 |
/
|
/sbin/nologin
|
| ntp | 38 | 38 |
/etc/ntp
|
/sbin/nologin
|
| canna | 39 | 39 |
/var/lib/canna
|
/sbin/nologin
|
| nscd | 28 | 28 |
/
|
/sbin/nologin
|
| rpc | 32 | 32 |
/
|
/sbin/nologin
|
| postfix | 89 | 89 |
/var/spool/postfix
|
/sbin/nologin
|
| mailman | 41 | 41 |
/var/mailman
|
/sbin/nologin
|
| named | 25 | 25 |
/var/named
|
/bin/false
|
| amanda | 33 | 6 |
var/lib/amanda/
|
/bin/bash
|
| postgres | 26 | 26 |
/var/lib/pgsql
|
/bin/bash
|
| exim | 93 | 93 |
/var/spool/exim
|
/sbin/nologin
|
| sshd | 74 | 74 |
/var/empty/sshd
|
/sbin/nologin
|
| rpcuser | 29 | 29 |
/var/lib/nfs
|
/sbin/nologin
|
| nsfnobody | 65534 | 65534 |
/var/lib/nfs
|
/sbin/nologin
|
| pvm | 24 | 24 |
/usr/share/pvm3
|
/bin/bash
|
| apache | 48 | 48 |
/var/www
|
/sbin/nologin
|
| xfs | 43 | 43 |
/etc/X11/fs
|
/sbin/nologin
|
| gdm | 42 | 42 |
/var/gdm
|
/sbin/nologin
|
| htt | 100 | 101 |
/usr/lib/im
|
/sbin/nologin
|
| mysql | 27 | 27 |
/var/lib/mysql
|
/bin/bash
|
| webalizer | 67 | 67 |
/var/www/usage
|
/sbin/nologin
|
| mailnull | 47 | 47 |
/var/spool/mqueue
|
/sbin/nologin
|
| smmsp | 51 | 51 |
/var/spool/mqueue
|
/sbin/nologin
|
| squid | 23 | 23 |
/var/spool/squid
|
/sbin/nologin
|
| ldap | 55 | 55 |
/var/lib/ldap
|
/bin/false
|
| netdump | 34 | 34 |
/var/crash
|
/bin/bash
|
| pcap | 77 | 77 |
/var/arpwatch
|
/sbin/nologin
|
| radiusd | 95 | 95 |
/
|
/bin/false
|
| radvd | 75 | 75 |
/
|
/sbin/nologin
|
| quagga | 92 | 92 |
/var/run/quagga
|
/sbin/login
|
| wnn | 49 | 49 |
/var/lib/wnn
|
/sbin/nologin
|
| dovecot | 97 | 97 |
/usr/libexec/dovecot
|
/sbin/nologin
|
/etc/group file.
| Group | GID | Members |
|---|---|---|
| root | 0 | root |
| bin | 1 | root, bin, daemon |
| daemon | 2 | root, bin, daemon |
| sys | 3 | root, bin, adm |
| adm | 4 | root, adm, daemon |
| tty | 5 | |
| disk | 6 | root |
| lp | 7 | daemon, lp |
| mem | 8 | |
| kmem | 9 | |
| wheel | 10 | root |
| 12 | mail, postfix, exim | |
| news | 13 | news |
| uucp | 14 | uucp |
| man | 15 | |
| games | 20 | |
| gopher | 30 | |
| dip | 40 | |
| ftp | 50 | |
| lock | 54 | |
| nobody | 99 | |
| users | 100 | |
| rpm | 37 | |
| utmp | 22 | |
| floppy | 19 | |
| vcsa | 69 | |
| dbus | 81 | |
| ntp | 38 | |
| canna | 39 | |
| nscd | 28 | |
| rpc | 32 | |
| postdrop | 90 | |
| postfix | 89 | |
| mailman | 41 | |
| exim | 93 | |
| named | 25 | |
| postgres | 26 | |
| sshd | 74 | |
| rpcuser | 29 | |
| nfsnobody | 65534 | |
| pvm | 24 | |
| apache | 48 | |
| xfs | 43 | |
| gdm | 42 | |
| htt | 101 | |
| mysql | 27 | |
| webalizer | 67 | |
| mailnull | 47 | |
| smmsp | 51 | |
| squid | 23 | |
| ldap | 55 | |
| netdump | 34 | |
| pcap | 77 | |
| quaggavt | 102 | |
| quagga | 92 | |
| radvd | 75 | |
| slocate | 21 | |
| wnn | 49 | |
| dovecot | 97 | |
| radiusd | 95 |
/etc/bashrc file. Traditionally on UNIX systems, the umask is set to 022, which allows only the user who created the file or directory to make modifications. Under this scheme, all other users, including members of the creator's group, are not allowed to make any modifications. However, under the UPG scheme, this "group protection" is not necessary since every user has their own private group.
/usr/share/emacs/site-lisp/ directory. Some people are trusted to modify the directory, but certainly not everyone is trusted. First create an emacs group, as in the following command:
/usr/sbin/groupadd emacs
emacs group, type:
chown -R root.emacs /usr/share/emacs/site-lisp
gpasswd command:
/usr/bin/gpasswd -a <username> emacs
chmod 775 /usr/share/emacs/site-lisp
emacs). Use the following command:
chmod 2775 /usr/share/emacs/site-lisp
emacs group can create and edit files in the /usr/share/emacs/site-lisp/ directory without the administrator having to change file permissions every time users write new files.
shadow-utils package). Doing so enhances the security of system authentication files. For this reason, the installation program enables shadow passwords by default.
/etc/passwd file to /etc/shadow, which is readable only by the root user.
/etc/login.defs file to enforce security policies.
shadow-utils package work properly whether or not shadow passwords are enabled. However, since password aging information is stored exclusively in the /etc/shadow file, any commands which create or modify password aging information do not work.
chage
gpasswd
/usr/sbin/usermod -e or -f options
/usr/sbin/useradd -e or -f options
man chage — A command to modify password aging policies and account expiration.
man gpasswd — A command to administer the /etc/group file.
man groupadd — A command to add groups.
man grpck — A command to verify the /etc/group file.
man groupdel — A command to remove groups.
man groupmod — A command to modify group membership.
man pwck — A command to verify the /etc/passwd and /etc/shadow files.
man pwconv — A tool to convert standard passwords to shadow passwords.
man pwunconv — A tool to convert shadow passwords to standard passwords.
man useradd — A command to add users.
man userdel — A command to remove users.
man usermod — A command to modify users.
man 5 group — The file containing group information for the system.
man 5 passwd — The file containing user information for the system.
man 5 shadow — The file containing passwords and account expiration information for the system.
system-config-printer at a shell prompt.
) beside a Workgroup to expand it. From the expanded list, select a printer.
computer name/printer share. In Figure 22.5, “Adding a SMB Printer”, the computer name is dellbox, while the printer share is r2.
guest for Windows servers, or nobody for Samba servers.
lpq. The last few lines look similar to the following:
Rank Owner/ID Class Job Files Size Time active user@localhost+902 A 902 sample.txt 2050 01:20:46
lpq outputlpq and then use the command lprm job number . For example, lprm 902 would cancel the print job in Example 22.1, “Example of lpq output”. You must have proper permissions to cancel a print job. You can not cancel print jobs that were started by other users unless you are logged in as root on the machine to which the printer is attached.
lpr sample.txt prints the text file sample.txt. The print filter determines what type of file it is and converts it into a format the printer can understand.
map lpr — The manual page for the lpr command that allows you to print files from the command line.
man lprm — The manual page for the command line utility to remove print jobs from the print queue.
man mpage — The manual page for the command line utility to print multiple pages on one sheet of paper.
man cupsd — The manual page for the CUPS printer daemon.
man cupsd.conf — The manual page for the CUPS printer daemon configuration file.
man classes.conf — The manual page for the class configuration file for CUPS.
locate command is updated daily. A system administrator can use automated tasks to perform periodic backups, monitor the system, run custom scripts, and more.
cron, at, and batch.
cronie RPM package must be installed and the crond service must be running. To determine if the package is installed, use the rpm -q cronie command. To determine if the service is running, use the command /sbin/service crond status.
/etc/crontab, contains the following lines:
SHELL=/bin/bash PATH=/sbin:/bin:/usr/sbin:/usr/bin MAILTO=root HOME=/ # run-parts 01 * * * * root run-parts /etc/cron.hourly 02 4 * * * root run-parts /etc/cron.daily 22 4 * * 0 root run-parts /etc/cron.weekly 42 4 1 * * root run-parts /etc/cron.monthly
SHELL variable tells the system which shell environment to use (in this example the bash shell), while the PATH variable defines the path used to execute commands. The output of the cron tasks are emailed to the username defined with the MAILTO variable. If the MAILTO variable is defined as an empty string (MAILTO=""), email is not sent. The HOME variable can be used to set the home directory to use when executing commands or scripts.
/etc/crontab file represents a task and has the following format:
minute hour day month dayofweek command
minute — any integer from 0 to 59
hour — any integer from 0 to 23
day — any integer from 1 to 31 (must be a valid day if a month is specified)
month — any integer from 1 to 12 (or the short name of the month such as jan or feb)
dayofweek — any integer from 0 to 7, where 0 or 7 represents Sunday (or the short name of the week such as sun or mon)
command — the command to execute (the command can either be a command such as ls /proc >> /tmp/proc or the command to execute a custom script)
1-4 means the integers 1, 2, 3, and 4.
3, 4, 6, 8 indicates those four specific integers.
/<integer>. For example, 0-59/2 can be used to define every other minute in the minute field. Step values can also be used with an asterisk. For instance, the value */3 can be used in the month field to run the task every third month.
/etc/crontab file, the run-parts script executes the scripts in the /etc/cron.hourly/, /etc/cron.daily/, /etc/cron.weekly/, and /etc/cron.monthly/ directories on an hourly, daily, weekly, or monthly basis respectively. The files in these directories should be shell scripts.
/etc/cron.d/ directory. All files in this directory use the same syntax as /etc/crontab. Refer to Example 23.1, “Crontab Examples” for examples.
# record the memory usage of the system every monday # at 3:30AM in the file /tmp/meminfo 30 3 * * mon cat /proc/meminfo >> /tmp/meminfo # run custom script the first day of every month at 4:10AM 10 4 1 * * /root/scripts/backup.sh
crontab utility. All user-defined crontabs are stored in the /var/spool/cron/ directory and are executed using the usernames of the users that created them. To create a crontab as a user, login as that user and type the command crontab -e to edit the user's crontab using the editor specified by the VISUAL or EDITOR environment variable. The file uses the same format as /etc/crontab. When the changes to the crontab are saved, the crontab is stored according to username and written to the file /var/spool/cron/username .
/etc/crontab file, the /etc/cron.d/ directory, and the /var/spool/cron/ directory every minute for any changes. If any changes are found, they are loaded into memory. Thus, the daemon does not need to be restarted if a crontab file is changed.
/etc/cron.allow and /etc/cron.deny files are used to restrict access to cron. The format of both access control files is one username on each line. Whitespace is not permitted in either file. The cron daemon (crond) does not have to be restarted if the access control files are modified. The access control files are read each time a user tries to add or delete a cron task.
cron.allow exists, only users listed in it are allowed to use cron, and the cron.deny file is ignored.
cron.allow does not exist, users listed in cron.deny are not allowed to use cron.
/sbin/service crond start. To stop the service, use the command /sbin/service crond stop. It is recommended that you start the service at boot time. Refer to Chapter 6, Controlling Access to Services for details on starting the cron service automatically at boot time.
at command is used to schedule a one-time task at a specific time and the batch command is used to schedule a one-time task to be executed when the systems load average drops below 0.8.
at or batch, the at RPM package must be installed, and the atd service must be running. To determine if the package is installed, use the rpm -q at command. To determine if the service is running, use the command /sbin/service atd status.
at time , where time time can be one of the following:
/usr/share/doc/at-<version>/timespec text file.
at command with the time argument, the at> prompt is displayed. Type the command to execute, press Enter, and type Ctrl+D . Multiple commands can be specified by typing each command followed by the Enter key. After typing all the commands, press Enter to go to a blank line and type Ctrl+D . Alternatively, a shell script can be entered at the prompt, pressing Enter after each line in the script, and typing Ctrl+D on a blank line to exit. If a script is entered, the shell used is the shell set in the user's SHELL environment, the user's login shell, or /bin/sh (whichever is found first).
atq to view pending jobs. Refer to Section 23.2.3, “Viewing Pending Jobs” for more information.
at command can be restricted. For more information, refer to Section 23.2.5, “Controlling Access to At and Batch” for details.
batch command.
batch command, the at> prompt is displayed. Type the command to execute, press Enter, and type Ctrl+D . Multiple commands can be specified by typing each command followed by the Enter key. After typing all the commands, press Enter to go to a blank line and type Ctrl+D . Alternatively, a shell script can be entered at the prompt, pressing Enter after each line in the script, and typing Ctrl+D on a blank line to exit. If a script is entered, the shell used is the shell set in the user's SHELL environment, the user's login shell, or /bin/sh (whichever is found first). As soon as the load average is below 0.8, the set of commands or script is executed.
atq to view pending jobs. Refer to Section 23.2.3, “Viewing Pending Jobs” for more information.
batch command can be restricted. For more information, refer to Section 23.2.5, “Controlling Access to At and Batch” for details.
at and batch jobs, use the atq command. The atq command displays a list of pending jobs, with each job on a line. Each line follows the job number, date, hour, job class, and username format. Users can only view their own jobs. If the root user executes the atq command, all jobs for all users are displayed.
at and batch include:
| Option | Description |
|---|---|
-f
| Read the commands or shell script from a file instead of specifying them at the prompt. |
-m
| Send email to the user when the job has been completed. |
-v
| Display the time that the job is executed. |
at and batch Command Line Options/etc/at.allow and /etc/at.deny files can be used to restrict access to the at and batch commands. The format of both access control files is one username on each line. Whitespace is not permitted in either file. The at daemon (atd) does not have to be restarted if the access control files are modified. The access control files are read each time a user tries to execute the at or batch commands.
at and batch commands, regardless of the access control files.
at.allow exists, only users listed in it are allowed to use at or batch, and the at.deny file is ignored.
at.allow does not exist, users listed in at.deny are not allowed to use at or batch.
at service, use the command /sbin/service atd start. To stop the service, use the command /sbin/service atd stop. It is recommended that you start the service at boot time. Refer to Chapter 6, Controlling Access to Services for details on starting the cron service automatically at boot time.
cron man page — overview of cron.
crontab man pages in sections 1 and 5 — The man page in section 1 contains an overview of the crontab file. The man page in section 5 contains the format for the file and some example entries.
/usr/share/doc/at-<version>/timespec contains more detailed information about the times that can be specified for cron jobs.
at man page — description of at and batch and their command line options.
syslogd. A list of log messages maintained by syslogd can be found in the /etc/syslog.conf configuration file.
/var/log/ directory. Some applications such as httpd and samba have a directory within /var/log/ for their log files.
logrotate package contains a cron task that automatically rotates log files according to the /etc/logrotate.conf configuration file and the configuration files in the /etc/logrotate.d/ directory. By default, it is configured to rotate every week and keep four weeks worth of previous log files.
Vi or Emacs. Some log files are readable by all users on the system; however, root privileges are required to read most log files.
gnome-system-log at a shell prompt.
Table of Contents
ps ax command displays a list of current system processes, including processes owned by other users. To display the owner alongside each process, use the ps aux command. This list is a static list; in other words, it is a snapshot of what was running when you invoked the command. If you want a constantly updated list of running processes, use top as described below.
ps output can be long. To prevent it from scrolling off the screen, you can pipe it through less:
ps aux | less
ps command in combination with the grep command to see if a process is running. For example, to determine if Emacs is running, use the following command:
ps ax | grep emacs
top command displays currently running processes and important information about them including their memory and CPU usage. The list is both real-time and interactive. An example of output from the top command is provided as follows:
top - 18:11:48 up 1 min, 1 user, load average: 0.68, 0.30, 0.11
Tasks: 122 total, 1 running, 121 sleeping, 0 stopped, 0 zombie
Cpu(s): 0.0%us, 0.5%sy, 0.0%ni, 93.4%id, 5.7%wa, 0.2%hi, 0.2%si, 0.0
Mem: 501924k total, 376496k used, 125428k free, 29664k buffers
Swap: 1015800k total, 0k used, 1015800k free, 189008k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
1601 root 40 0 20172 1084 920 S 0.3 0.2 0:00.08 hald-addon-sto
1998 silas 40 0 14984 1160 880 R 0.3 0.2 0:00.13 top
1 root 40 0 19160 1412 1156 S 0.0 0.3 0:00.96 init
2 root 40 0 0 0 0 S 0.0 0.0 0:00.01 kthreadd
3 root RT 0 0 0 0 S 0.0 0.0 0:00.05 migration/0
4 root 20 0 0 0 0 S 0.0 0.0 0:00.00 ksoftirqd/0
5 root RT 0 0 0 0 S 0.0 0.0 0:00.00 watchdog/0
6 root RT 0 0 0 0 S 0.0 0.0 0:00.04 migration/1
7 root 20 0 0 0 0 S 0.0 0.0 0:00.00 ksoftirqd/1
8 root RT 0 0 0 0 S 0.0 0.0 0:00.00 watchdog/1
9 root 20 0 0 0 0 S 0.0 0.0 0:00.00 events/0
10 root 20 0 0 0 0 S 0.0 0.0 0:00.01 events/1
11 root 20 0 0 0 0 S 0.0 0.0 0:00.00 cpuset
12 root 20 0 0 0 0 S 0.0 0.0 0:00.00 khelper
[output truncated]
top, press the q key.
top commands” contains useful interactive commands that you can use with top. For more information, refer to the top(1) manual page.
| Command | Description |
|---|---|
| Space | Immediately refresh the display |
| h | Display a help screen |
| k | Kill a process. You are prompted for the process ID and the signal to send to it. |
| n | Change the number of processes displayed. You are prompted to enter the number. |
| u | Sort by user. |
| M | Sort by memory usage. |
| P | Sort by CPU usage. |
top commandstop, you can use the GNOME System Monitor. To start it from the desktop, select > > or type gnome-system-monitor at a shell prompt (such as an XTerm). Select the Process Listing tab.
free command displays the total amount of physical memory and swap space for the system as well as the amount of memory that is used, free, shared, in kernel buffers, and cached.
total used free shared buffers cached Mem: 645712 549720 95992 0 176248 224452 -/+ buffers/cache: 149020 496692 Swap: 1310712 0 1310712
free -m shows the same information in megabytes, which are easier to read.
total used free shared buffers cached Mem: 630 536 93 0 172 219 -/+ buffers/cache: 145 485 Swap: 1279 0 1279
free, you can use the GNOME System Monitor. To start it from the desktop, go to > > or type gnome-system-monitor at a shell prompt (such as an XTerm). Click on the Resources tab.
df command reports the system's disk space usage. If you type the command df at a shell prompt, the output looks similar to the following:
Filesystem 1K-blocks Used Available Use% Mounted on /dev/mapper/VolGroup00-LogVol00 11675568 6272120 4810348 57% / /dev/sda1 100691 9281 86211 10% /boot none 322856 0 322856 0% /dev/shm
df -h. The -h argument stands for human-readable format. The output looks similar to the following:
Filesystem Size Used Avail Use% Mounted on /dev/mapper/VolGroup00-LogVol00 12G 6.0G 4.6G 57% / /dev/sda1 99M 9.1M 85M 10% /boot none 316M 0 316M 0% /dev/shm
/dev/shm. This entry represents the system's virtual memory file system.
du command displays the estimated amount of space being used by files in a directory. If you type du at a shell prompt, the disk usage for each of the subdirectories is displayed in a list. The grand total for the current directory and subdirectories are also shown as the last line in the list. If you do not want to see the totals for all the subdirectories, use the command du -hs to see only the grand total for the directory in human-readable format. Use the du --help command to see more options.
gnome-system-monitor at a shell prompt (such as an XTerm). Select the File Systems tab to view the system's partitions. The figure below illustrates the File Systems tab.
hwbrowser at a shell prompt. As shown in Figure 25.4, “ Hardware Browser ”, it displays your CD-ROM devices, diskette drives, hard drives and their partitions, network devices, pointing devices, system devices, and video cards. Click on the category name in the left menu, and the information is displayed.
hal-device-manager. Depending on your installation preferences, the graphical menu above may start this application or the Hardware Browser when clicked. The figure below illustrates the Device Manager window.
lspci command to list all PCI devices. Use the command lspci -v for more verbose information or lspci -vv for very verbose output.
lspci can be used to determine the manufacturer, model, and memory size of a system's video card:
00:00.0 Host bridge: ServerWorks CNB20LE Host Bridge (rev 06) 00:00.1 Host bridge: ServerWorks CNB20LE Host Bridge (rev 06) 00:01.0 VGA compatible controller: S3 Inc. Savage 4 (rev 04) 00:02.0 Ethernet controller: Intel Corp. 82557/8/9 [Ethernet Pro 100] (rev 08) 00:0f.0 ISA bridge: ServerWorks OSB4 South Bridge (rev 50) 00:0f.1 IDE interface: ServerWorks OSB4 IDE Controller 00:0f.2 USB Controller: ServerWorks OSB4/CSB5 OHCI USB Controller (rev 04) 01:03.0 SCSI storage controller: Adaptec AIC-7892P U160/m (rev 02) 01:05.0 RAID bus controller: IBM ServeRAID Controller
lspci is also useful to determine the network card in your system if you do not know the manufacturer or model number.
ps --help — Displays a list of options that can be used with ps.
top manual page — Type man top to learn more about top and its many options.
free manual page — type man free to learn more about free and its many options.
df manual page — Type man df to learn more about the df command and its many options.
du manual page — Type man du to learn more about the du command and its many options.
lspci manual page — Type man lspci to learn more about the lspci command and its many options.
oprofile RPM package must be installed to use this tool.
--separate=library option is used.
opreport does not associate samples for inline functions' properly — opreport uses a simple address range mechanism to determine which function an address is in. Inline function samples are not attributed to the inline function but rather to the function the inline function was inserted into.
opcontrol --reset to clear out the samples from previous runs.
oprofile package.
| Command | Description |
|---|---|
ophelp
|
Displays available events for the system's processor along with a brief description of each.
|
opimport
|
Converts sample database files from a foreign binary format to the native format for the system. Only use this option when analyzing a sample database from a different architecture.
|
opannotate
|
Creates annotated source for an executable if the application was compiled with debugging symbols. Refer to Section 26.5.4, “Using opannotate ” for details.
|
opcontrol
|
Configures what data is collected. Refer to Section 26.2, “Configuring OProfile” for details.
|
opreport
|
Retrieves profile data. Refer to Section 26.5.1, “Using
opreport ” for details.
|
oprofiled
|
Runs as a daemon to periodically write sample data to disk.
|
opcontrol utility to configure OProfile. As the opcontrol commands are executed, the setup options are saved to the /root/.oprofile/daemonrc file.
opcontrol --setup --vmlinux=/usr/lib/debug/lib/modules/`uname -r`/vmlinux
debuginfo package must be installed (which contains the uncompressed kernel) in order to monitor the kernel.
opcontrol --setup --no-vmlinux
oprofile kernel module, if it is not already loaded, and creates the /dev/oprofile/ directory, if it does not already exist. Refer to Section 26.6, “Understanding /dev/oprofile/ ” for details about this directory.
oprofile module can be loaded from it.
| Processor |
cpu_type
| Number of Counters |
|---|---|---|
| Pentium Pro | i386/ppro | 2 |
| Pentium II | i386/pii | 2 |
| Pentium III | i386/piii | 2 |
| Pentium 4 (non-hyper-threaded) | i386/p4 | 8 |
| Pentium 4 (hyper-threaded) | i386/p4-ht | 4 |
| Athlon | i386/athlon | 4 |
| AMD64 | x86-64/hammer | 4 |
| TIMER_INT | timer | 1 |
| IBM eServer iSeries and pSeries | timer | 1 |
| ppc64/power4 | 8 | |
| ppc64/power5 | 6 | |
| ppc64/970 | 8 | |
| IBM eServer S/390 and S/390x | timer | 1 |
| IBM eServer zSeries | timer | 1 |
timer is used as the processor type if the processor does not have supported performance monitoring hardware.
timer is used, events cannot be set for any processor because the hardware does not have support for hardware performance counters. Instead, the timer interrupt is used for profiling.
timer is not used as the processor type, the events monitored can be changed, and counter 0 for the processor is set to a time-based event by default. If more than one counter exists on the processor, the counters other than counter 0 are not set to an event by default. The default events monitored are shown in Table 26.3, “Default Events”.
| Processor | Default Event for Counter | Description |
|---|---|---|
| Pentium Pro, Pentium II, Pentium III, Athlon, AMD64 | CPU_CLK_UNHALTED | The processor's clock is not halted |
| Pentium 4 (HT and non-HT) | GLOBAL_POWER_EVENTS | The time during which the processor is not stopped |
| TIMER_INT | (none) | Sample for each timer interrupt |
| ppc64/power4 | CYCLES | Processor Cycles |
| ppc64/power5 | CYCLES | Processor Cycles |
| ppc64/970 | CYCLES | Processor Cycles |
ls -d /dev/oprofile/[0-9]*
ophelp
opcontrol:
opcontrol --event=<event-name>:<sample-rate>
<event-name> with the exact name of the event from ophelp, and replace <sample-rate> with the number of events between samples.
cpu_type is not timer, each event can have a sampling rate set for it. The sampling rate is the number of events between each sample snapshot.
opcontrol --event=<event-name>:<sample-rate>
<sample-rate> with the number of events to wait before sampling again. The smaller the count, the more frequent the samples. For events that do not happen frequently, a lower count may be needed to capture the event instances.
ophelp command. The values for each unit mask are listed in hexadecimal format. To specify more than one unit mask, the hexadecimal values must be combined using a bitwise or operation.
opcontrol --event=<event-name>:<sample-rate>:<unit-mask>
opcontrol --event=<event-name>:<sample-rate>:<unit-mask>:0
opcontrol --event=<event-name>:<sample-rate>:<unit-mask>:1
opcontrol --event=<event-name>:<sample-rate>:<unit-mask>:<kernel>:0
opcontrol --event=<event-name>:<sample-rate>:<unit-mask>:<kernel>:1
opcontrol --separate=<choice>
<choice> can be one of the following:
none — do not separate the profiles (default)
library — generate per-application profiles for libraries
kernel — generate per-application profiles for the kernel and kernel modules
all — generate per-application profiles for libraries and per-application profiles for the kernel and kernel modules
--separate=library is used, the sample file name includes the name of the executable as well as the name of the library.
oprofile is restarted.
opcontrol --start
Using log file /var/lib/oprofile/oprofiled.log Daemon started. Profiler running.
/root/.oprofile/daemonrc are used.
oprofiled, is started; it periodically writes the sample data to the /var/lib/oprofile/samples/ directory. The log file for the daemon is located at /var/lib/oprofile/oprofiled.log.
opcontrol --shutdown
<name> with a unique descriptive name for the current session.
opcontrol --save=<name>
/var/lib/oprofile/samples/name/ is created and the current sample files are copied to it.
oprofiled, collects the samples and writes them to the /var/lib/oprofile/samples/ directory. Before reading the data, make sure all data has been written to this directory by executing the following command as root:
opcontrol --dump
/bin/bash becomes:
\{root\}/bin/bash/\{dep\}/\{root\}/bin/bash/CPU_CLK_UNHALTED.100000
opreport
opannotate
oparchive can be used to address this problem.
opreport opreport tool provides an overview of all the executables being profiled.
Profiling through timer interrupt TIMER:0| samples| %| ------------------ 25926 97.5212 no-vmlinux 359 1.3504 pi 65 0.2445 Xorg 62 0.2332 libvte.so.4.4.0 56 0.2106 libc-2.3.4.so 34 0.1279 libglib-2.0.so.0.400.7 19 0.0715 libXft.so.2.1.2 17 0.0639 bash 8 0.0301 ld-2.3.4.so 8 0.0301 libgdk-x11-2.0.so.0.400.13 6 0.0226 libgobject-2.0.so.0.400.7 5 0.0188 oprofiled 4 0.0150 libpthread-2.3.4.so 4 0.0150 libgtk-x11-2.0.so.0.400.13 3 0.0113 libXrender.so.1.2.2 3 0.0113 du 1 0.0038 libcrypto.so.0.9.7a 1 0.0038 libpam.so.0.77 1 0.0038 libtermcap.so.2.0.8 1 0.0038 libX11.so.6.2 1 0.0038 libgthread-2.0.so.0.400.7 1 0.0038 libwnck-1.so.4.9.0
opreport man page for a list of available command line options, such as the -r option used to sort the output from the executable with the smallest number of samples to the one with the largest number of samples.
opreport on a Single Executableopreport:
opreport <mode> <executable>
<executable> must be the full path to the executable to be analyzed. <mode> must be one of the following:
-l opreport -l /lib/tls/libc-<version>.so:
samples % symbol name 12 21.4286 __gconv_transform_utf8_internal 5 8.9286 _int_malloc 4 7.1429 malloc 3 5.3571 __i686.get_pc_thunk.bx 3 5.3571 _dl_mcount_wrapper_check 3 5.3571 mbrtowc 3 5.3571 memcpy 2 3.5714 _int_realloc 2 3.5714 _nl_intern_locale_data 2 3.5714 free 2 3.5714 strcmp 1 1.7857 __ctype_get_mb_cur_max 1 1.7857 __unregister_atfork 1 1.7857 __write_nocancel 1 1.7857 _dl_addr 1 1.7857 _int_free 1 1.7857 _itoa_word 1 1.7857 calc_eclosure_iter 1 1.7857 fopen@@GLIBC_2.1 1 1.7857 getpid 1 1.7857 memmove 1 1.7857 msort_with_tmp 1 1.7857 strcpy 1 1.7857 strlen 1 1.7857 vfprintf 1 1.7857 write
-r in conjunction with the -l option.
-i <symbol-name> opreport -l -i __gconv_transform_utf8_internal /lib/tls/libc-<version>.so:
samples % symbol name 12 100.000 __gconv_transform_utf8_internal
-d -l. For example, the following output is from the command opreport -l -d __gconv_transform_utf8_internal /lib/tls/libc-<version>.so:
vma samples % symbol name 00a98640 12 100.000 __gconv_transform_utf8_internal 00a98640 1 8.3333 00a9868c 2 16.6667 00a9869a 1 8.3333 00a986c1 1 8.3333 00a98720 1 8.3333 00a98749 1 8.3333 00a98753 1 8.3333 00a98789 1 8.3333 00a98864 1 8.3333 00a98869 1 8.3333 00a98b08 1 8.3333
-l option except that for each symbol, each virtual memory address used is shown. For each virtual memory address, the number of samples and percentage of samples relative to the number of samples for the symbol is displayed.
-x <symbol-name> session:<name> /var/lib/oprofile/samples/ directory.
$ opreport /ext3
CPU: AMD64 processors, speed 797.948 MHz (estimated)
Counted DATA_CACHE_ACCESSES events (Data cache accesses) with a unit mask of 0x00 (No unit mask) count 500000
Counted DATA_CACHE_MISSES events (Data cache misses) with a unit mask of 0x00 (No unit mask) count 500000
DATA_CACHE_ACC...|DATA_CACHE_MIS...|
samples| %| samples| %|
------------------------------------
148721 100.000 1493 100.000 ext3
# ln -s /lib/modules/`uname -r`/kernel/fs/ext3/ext3.ko /ext3
# opreport image:/ext3 -l|more
warning: could not check that the binary file /ext3 has not been modified since the profile was taken. Results may be inaccurate.
CPU: AMD64 processors, speed 797.948 MHz (estimated)
Counted DATA_CACHE_ACCESSES events (Data cache accesses) with a unit mask of 0x00 (No unit mask) count 500000
Counted DATA_CACHE_MISSES events (Data cache misses) with a unit mask of 0x00 (No unit mask) count 500000
samples % samples % symbol name
16728 11.2479 7 0.4689 ext3_group_sparse
16454 11.0637 4 0.2679 ext3_count_free_blocks
14583 9.8056 51 3.4159 ext3_fill_super
8281 5.5681 129 8.6403 ext3_ioctl
7810 5.2514 62 4.1527 ext3_write_info
7286 4.8991 67 4.4876 ext3_ordered_writepage
6509 4.3767 130 8.7073 ext3_new_inode
6378 4.2886 156 10.4488 ext3_new_block
5932 3.9887 87 5.8272 ext3_xattr_block_list
...
opannotate opannotate tool tries to match the samples for particular instructions to the corresponding lines in the source code. The resulting files generated should have the samples for the lines at the left. It also puts in a comment at the beginning of each function listing the total samples for the function.
-g option. By default, Fedora packages are not compiled with this option.
opannotate is as follows:
opannotate --search-dirs <src-dir> --source <executable>
opannotate man page for a list of additional command line options.
/dev/oprofile/ /dev/oprofile/ directory contains the file system for OProfile. Use the cat command to display the values of the virtual files in this file system. For example, the following command displays the type of processor OProfile detected:
cat /dev/oprofile/cpu_type
/dev/oprofile/ for each counter. For example, if there are 2 counters, the directories /dev/oprofile/0/ and dev/oprofile/1/ exist.
count — The interval between samples.
enabled — If 0, the counter is off and no samples are collected for it; if 1, the counter is on and samples are being collected for it.
event — The event to monitor.
kernel — If 0, samples are not collected for this counter event when the processor is in kernel-space; if 1, samples are collected even if the processor is in kernel-space.
unit_mask — Defines which unit masks are enabled for the counter.
user — If 0, samples are not collected for the counter event when the processor is in user-space; if 1, samples are collected even if the processor is in user-space.
cat command. For example:
cat /dev/oprofile/0/count
opreport can be used to determine how much processor time an application or service uses. If the system is used for multiple services but is under performing, the services consuming the most processor time can be moved to dedicated systems.
CPU_CLK_UNHALTED event can be monitored to determine the processor load over a given period of time. This data can then be used to determine if additional processors or a faster processor might improve system performance.
oprof_start command as root at a shell prompt. To use the graphical interface, you will need to have the oprofile-gui package installed.
/root/.oprofile/daemonrc, and the application exits. Exiting the application does not stop OProfile from sampling.
oprof_start interface
vmlinux file for the kernel to monitor in the Kernel image file text field. To configure OProfile not to monitor the kernel, select No kernel image.
oprofiled daemon log includes more information.
opcontrol --separate=kernel command. If Per-application shared libs samples files is selected, OProfile generates per-application profiles for libraries. This is equivalent to the opcontrol --separate=library command.
opcontrol --dump command.
/usr/share/doc/oprofile-<version>/oprofile.html — OProfile Manual
oprofile man page — Discusses opcontrol, opreport, opannotate, and ophelp
abrtd system service, abrt-applet, which runs in the user's Notification Area, and the Automatic Bug-Reporting Tool GUI application.
abrtd daemon, configuration file, and localization and other files.
gdb, the GNU debugger, to transparently provide relevant crash information.
abrtd daemon configured to run at boot time, and abrt-applet is running in the Notification Area of your desktop session. You can ensure that ABRT is installed by running, as root:
~]# yum install abrt-desktop
abrtd daemon is running by issuing the command:
~]# service abrtd status
abrt (pid 1559) is running...
abrt is stopped, you can start the abrtd daemon by running, as root:
~]# service abrtd start
Starting abrt daemon: [ OK ]
abrtd service initializes at startup time by running the chkconfig abrtd on command as root.
abrt-applet program as a normal user when logged into your desktop session, or by arranging for it to be started when the GUI session is initialized. For example, on the GNOME desktop, this can be configured in → → → .
abrt-applet detects a crash, it displays a red alarm icon in the Notifcation Area. You can open the GUI application by clicking on this icon.
/etc/abrt/abrt.conf. ABRT plugins can be configured through their config files, located in the /etc/abrt/plugins/ directory.
abrt.conf configuration file, you must restart the abrtd daemon—as root—for the new settings to take effect:
~]# service abrtd restart
/etc/abrt/abrt.conf.
<yes/no> OpenGPGCheck directive to yes (the default setting) tells ABRT to only analyze and handle crashes in applications provided by packages which are signed by the GPG keys whose locations are listed in the /etc/abrt/gpg_keys file. Setting OpenGPGCheck to no tells ABRT to catch crashes in all programs.
<additional_packages> ] BlackList option will not be handled by ABRT. If you want ABRT to ignore other packages, list them here separated by commas.
<size_in_megabytes> 1000 MB. Once the quota specified here has been met, ABRT will no longer catch and save program crash information.
sosreport command immediately after an application crash. You can turn this behavior off by commenting out this line. For further fine-tuning, you can add SOSreport to either the CCpp or Python options to make ABRT run sosreport after C and C++ or Python application crashes, respectively.
<time> = <action_to_run> [ Cron ] section of abrt.conf allows you to specify the exact time, or elapsed amount of time between, when ABRT should run a certain action, such as scanning for kernel oopses or performing file transfers. You can list further actions to run by appending them to the end of this section.
# Which Action plugins to run repeatedly [ Cron ] # h:m - at h:m # s - every s seconds 120 = KerneloopsScanner #02:00 = FileTransfer
<time_in_seconds> = <action_to_run> or <hh:mm> = <action_to_run> , where hh (hour) is in the range 00-23 (all hours less than 10 should be zero-filled, i.e. preceded by a 0), and mm (minute) is 00-59, zero-filled likewise.
[AnalyzerActionsAndReporters] section in abrt.conf specifies which plugins are to be used to report crash data. As of version 1.0.0, the default abrt.conf contains:
[ AnalyzerActionsAndReporters ]
Kerneloops = KerneloopsReporter
CCpp = Bugzilla, Logger
Python = Bugzilla, Logger
plugins/*.conf file. For example, plugins/Bugzilla.conf specifies which Bugzilla URL to use (set to https://bugzilla.redhat.com/ by default), the user's login name, password for logging in to the Bugzilla site, etc.
abrt-cli --get-list:
~]# abrt-cli --get-list
0.
UID : 501
UUID : d074c2882400b3ff245415e676ed53f22bb8e7b5
Package : gnome-packagekit-2.28.2-0.1.20091030git.fc12
Executable : /usr/bin/gpk-application
Crash Time : Wed 18 Nov 2009 12:07:40 PM CET
Crash Count: 2
1.
UID : 501
UUID : 52d0d2f64f0b07fb0e626ecdfa4ac4faadc38258
Package : gnome-commander-1.3-0.3.git_D20090929T1100_13dev.fc12
Executable : /usr/libexec/gnome-commander/gnome-commander
Crash Time : Wed 18 Nov 2009 04:58:46 PM CET
Crash Count: 1
UID: field shows the ID of the user which ran the program that caused the crash. It is useful when abrt-cli is executed with superuser privileges and it lists crashes from all users. The Package field shows the name and version of the Fedora package that contains the program, and the Executable field shows the location of the binary or script that crashed. The Crash Count field indicates how many times the same crash happened.
abrt-cli --report <UUID>, where UUID is a field from abrt-cli --get-list. You do not need to remember the exact UUID; either use a mouse to copy and paste it, or use bash completion (write first few characters of the UUID and press <TAB>).
~]#abrt-cli --report 52d<TAB> ~]#abrt-cli --report 52d0d2f64f0b07fb0e626ecdfa4ac4faadc38258>> Starting report creation...
abrt-cli opens a text editor with the content of the report. You can see what is being reported, and you can fill in instructions on how to reproduce the crash and other comments. You should also check the backtrace, because the backtrace might be sent to a public server and viewed by anyone, depending on the plugin settings.
abrt-cli uses the editor defined in the ABRT_EDITOR environment variable. If the variable is not defined, it checks the VISUAL and EDITOR variables. If none of these variables is set, vi is used. You can set the preferred editor in your .bashrc configuration file. For example, if you prefer GNU Emacs, add the following line to the file:
exportVISUAL=emacs
abrt-cli --delete <UUID> .
rpm command instead of yum.
/usr/share/doc/kernel-doc-<kernel_version>/ directory.
rpmbuild command. For more information on obtaining and installing the kernel source package, refer to the latest updated Fedora 13 Release Notes (and their updates) at http://www.redhat.com/docs/manuals/enterprise/
VFAT file system. You can create bootable USB media on media formatted as ext2, ext3, or VFAT .
4 GB is required for a distribution DVD image, around 700 MB for a distribution CD image, or around 10 MB for a minimal boot media image.
boot.iso file from a Fedora installation DVD, or installation CD-ROM#1, and you need a USB storage device formatted with the VFAT file system and around 16 MB of free space. The following procedure will not affect existing files on the USB storage device unless they have the same path names as the files that you copy onto it. To create USB boot media, perform the following commands as the root user:
~]# syslinux /dev/sdX1
sdX is the device name.
boot.iso and the USB storage device:
~]# mkdir /mnt/isoboot /mnt/diskboot
boot.iso:
~]# mount -o loop boot.iso /mnt/isoboot
~]# mount /dev/<sdX1> /mnt/diskboot
boot.iso to the USB storage device:
~]# cp /mnt/isoboot/isolinux/* /mnt/diskboot
isolinux.cfg file from boot.iso as the syslinux.cfg file for the USB device:
~]# grep -v local /mnt/isoboot/isolinux/isolinux.cfg > /mnt/diskboot/syslinux.cfg
boot.iso and the USB storage device:
~]# umount /mnt/isoboot /mnt/diskboot
mkbootdisk command as root. Refer to the mkbootdisk man page for usage information.
yum list installed "kernel-*" at a shell prompt. The output will comprise some or all of the following packages, depending on the system's architecture, and the version numbers may differ:
~]$ yum list installed "kernel-*"
kernel.x86_64 2.6.32-17.el6 installed
kernel-doc.noarch 2.6.32-17.el6 installed
kernel-firmware.noarch 2.6.32-17.el6 installed
kernel-headers.x86_64 2.6.32-17.el6 installed
<variant>-<version>.<arch>.rpm, where <variant> is one of either PAE, xen, and so forth. The <arch> is one of the following:
x86_64 for the AMD64 and Intel EM64T architectures
ppc64 for the IBM® eServer™ pSeries™ architecture
s390x for the IBM® eServer™ System z® architecture
i686 for Intel® Pentium® II, Intel® Pentium® III, Intel® Pentium® 4, AMD Athlon®, and AMD Duron® systems
-i argument with the rpm command to keep the old kernel. Do not use the -U option, since it overwrites the currently installed kernel, which creates boot loader problems. For example:
~]# rpm -ivh kernel-<kernel_version>.<arch>.rpm
initramfs by running the dracut command. However, you usually don't need to create an initramfs manually: this step is automatically performed if the kernel and its associated packages are installed or upgraded from RPM packages distributed by The Fedora Project.
initramfs corresponding to your current kernel version exists and is specified correctly in the grub.conf configuration file by following this procedure:
/boot/ directory and find the kernel (vmlinuz-<kernel_version> ) and initramfs-<kernel_version> with the latest (most recent) version number:
~]# ls /boot/
config-2.6.32.10-90.fc12.x86_64
config-2.6.32.11-99.fc12.x86_64
config-2.6.32.9-70.fc12.x86_64
efi
elf-memtest86+-4.00
grub
initramfs-2.6.32.10-90.fc12.x86_64.img
initramfs-2.6.32.11-99.fc12.x86_64.img
initramfs-2.6.32.9-70.fc12.x86_64.img
lost+found
memtest86+-4.00
System.map-2.6.32.10-90.fc12.x86_64
System.map-2.6.32.11-99.fc12.x86_64
System.map-2.6.32.9-70.fc12.x86_64
vmlinuz-2.6.32.10-90.fc12.x86_64
vmlinuz-2.6.32.11-99.fc12.x86_64
vmlinuz-2.6.32.9-70.fc12.x86_64
/boot/),
vmlinuz-2.6.32.10-90.fc12.x86_64, and
initramfs file matching our kernel version, initramfs-2.6.32.10-90.fc12.x86_64.img, also exists.
/boot/ directory you may find several initrd-<version>kdump.img files. These are special files created by the Kdump mechanism for kernel debugging purposes, are not used to boot the system, and can safely be ignored.
initramfs-<kernel_version> file does not match the version of the latest kernel in /boot/, or, in certain other situations, you may need to generate an initramfs file with the Dracut utility. Simply invoking dracut as root without options causes it to generate an initramfs file in the /boot/ directory for the latest kernel present in that directory:
~]# dracut
--force option if you want dracut to overwrite an existing initramfs (for example, if your initramfs has become corrupt). Otherwise dracut will refuse to overwrite the existing initramfs file:
~]# dracut
Will not override existing initramfs (/boot/initramfs-2.6.32.11-99.fc12.x86_64.img) without --force
dracut <initramfs_name> <kernel_version> :
~]# dracut "initramfs-$(uname -r).img" $(uname -r)
.ko) inside the parentheses of the add_dracutmodules="<module> [<more_modules> ]" directive of the /etc/dracut.conf configuration file. You can list the file contents of an initramfs image file created by dracut by using the lsinitrd <initramfs_file> command:
~]# lsinitrd initramfs-2.6.32.11-99.fc12.x86_64.img
initramfs-2.6.32.11-99.fc12.x86_64.img:
========================================================================
drwxr-xr-x 23 root root 0 Apr 12 05:41 .
drwxr-xr-x 2 root root 0 Apr 12 05:41 mount
-rwxr-xr-x 1 root root 934 Jan 15 14:07 mount/99mount-root.sh
-rwxr-xr-x 1 root root 230 Jan 15 14:07 mount/10resume.sh
output truncated
man dracut and man dracut.conf for more information on options and usage.
grub.conf configuration file in the /boot/grub/ directory to ensure that an initrd initramfs-<kernel_version>.img exists for the kernel version you are booting. Refer to Section 28.6, “Verifying the Boot Loader” for more information.
addRamDisk command. This step is performed automatically if the kernel and its associated packages are installed or upgraded from the RPM packages distributed by The Fedora Project; thus, it does not need to be executed manually. To verify that it was created, use the command ls -l /boot/ to make sure the /boot/vmlinitrd-<kernel_version> file already exists (the <kernel_version> rpm, the kernel package creates an entry in the boot loader configuration file for that new kernel. However, rpm does not configure the new kernel to boot as the default kernel. You must do this manually when installing a new kernel with rpm.
rpm to ensure that the configuration is correct. Otherwise, the system may not be able to boot into Fedora properly. If this happens, boot the system with the boot media created earlier and re-configure the boot loader.
| Architecture | Boot Loader | Refer to |
|---|---|---|
| x86 | GRUB | Section 28.6.1, “Configuring the GRUB Boot Loader” |
| AMD® AMD64 or Intel 64® | GRUB | Section 28.6.1, “Configuring the GRUB Boot Loader” |
| IBM® eServer™ System i™ | OS/400® | Section 28.6.2, “Configuring the OS/400® Boot Loader” |
| IBM® eServer™ System p™ | YABOOT | Section 28.6.3, “Configuring the YABOOT Boot Loader” |
| IBM® System z® | z/IPL |
/boot/grub/grub.conf, contains a few lines with directives, such as default, timeout, splashimage and hiddenmenu (the last directive has no argument). The remainder of the file contains 4-line stanzas that each refer to an installed kernel. These stanzas always start with a title entry, after which the associated root, kernel and initrd directives should always be indented. Ensure that each stanza starts with a title that contains a version number (in parentheses) that matches the version number in the kernel /vmlinuz-<version_number> line of the same stanza.
# grub.conf generated by anaconda
#
# Note that you do not have to rerun grub after making changes to this file
# NOTICE: You have a /boot partition. This means that
# all kernel and initrd paths are relative to /boot/, eg.
# root (hd0,0)
# kernel /vmlinuz-version ro root=/dev/sda2
# initrd /initramfs-[generic-]version.img
#boot=/dev/sda
default=1
timeout=0
splashimage=(hd0,0)/grub/splash.xpm.gz
hiddenmenu
title Fedora (2.6.32.11-99.fc12.x86_64)
root (hd0,0)
kernel /vmlinuz-2.6.32.11-99.fc12.x86_64 ro root=UUID=39e5f931-5dd5-4a90-a0cf-52996767d592 noiswmd LANG=en_US.UTF-8 SYSFONT=latarcyrheb-sun16 KEYBOARDTYPE=pc KEYTABLE=dvorak rhgb quiet
initrd /initramfs-2.6.32.11-99.fc12.x86_64.img
title Fedora (2.6.32.10-90.fc12.x86_64)
root (hd0,0)
kernel /vmlinuz-2.6.32.10-90.fc12.x86_64 ro root=UUID=39e5f931-5dd5-4a90-a0cf-52996767d592 noiswmd LANG=en_US.UTF-8 SYSFONT=latarcyrheb-sun16 KEYBOARDTYPE=pc KEYTABLE=dvorak rhgb quiet
initrd /initramfs-2.6.32.10-90.fc12.x86_64.img
title Fedora (2.6.32.9-70.fc12.x86_64)
root (hd0,0)
kernel /vmlinuz-2.6.32.9-70.fc12.x86_64 ro root=UUID=39e5f931-5dd5-4a90-a0cf-52996767d592 noiswmd LANG=en_US.UTF-8 SYSFONT=latarcyrheb-sun16 KEYBOARDTYPE=pc KEYTABLE=dvorak rhgb quiet
initrd /initramfs-2.6.32.9-70.fc12.x86_64.img
/boot/ partition was created, the paths to the kernel and the initramfs image are relative to /boot/. This is the case in Example 28.2, “/boot/grub/grub.conf”, above. Therefore the initrd /initramfs-2.6.32.11-99.fc12.x86_64.img line in the first kernel stanza means that the initramfs image is actually located at /boot/initramfs-2.6.32.11-99.fc12.x86_64.img when the root file system is mounted, and likewise for the kernel path (for example: kernel /vmlinuz-2.6.32.11-99.fc12.x86_64 ) in each stanza of grub.conf.
grub.conf, the initrd directive must point to the location (relative to the /boot/ directory if it is on a separate partition), of the initramfs file corresponding to the same kernel version. This directive is called initrd because the previous tool which created initial RAM disk images, mkinitrd, created what were known as initrd files. Thus the grub.conf directive remains initrd to maintain compatibility with other tools. The file-naming convention of systems using the dracut utility to create the initial RAM disk image is: initramfs-<kernel_version>.img
mkinitrd. For information on using Dracut, refer to Section 28.5, “Verifying the Initial RAM Disk Image”.
kernel /vmlinuz-<kernel_version> line matches the version number of the initramfs image given on the initrd /initramfs-<kernel_version>.img line of each stanza. Refer to Procedure 28.1, “Verifying the Initial RAM Disk Image” for more information.
default= directive tells GRUB which kernel to boot by default. Each title in grub.conf represents a bootable kernel. GRUB counts the titled stanzas representing bootable kernels starting with 0. In Example 28.2, “/boot/grub/grub.conf”, the line default=1 indicates that GRUB will boot, by default, the second kernel entry, i.e. title Fedora (2.6.32.10-90.fc12.x86_64).
title entry in grub.conf, we would need to change the default value to 0.
rpm, verify that /boot/grub/grub.conf is correct, change the default= value to the new kernel (while remembering to count from 0), and reboot the computer into the new kernel (ensure your hardware is detected by watching the boot process output).
timeout directive in grub.conf to 0, GRUB will not display its list of bootable kernels when the system starts up. In order to display this list when booting, press and hold any alphanumeric key while and immediately after BIOS information is displayed, and GRUB will present you with the GRUB menu.
/boot/vmlinitrd-<kernel-version> file is installed when you upgrade the kernel. However, you must use the dd command to configure the system to boot the new kernel.
cat /proc/iSeries/mf/side to determine the default side (either A, B, or C).
<kernel-version> is the version of the new kernel and <side> is the side from the previous command:
dd if=/boot/vmlinitrd-<kernel-version> of=/proc/iSeries/mf/<side>/vmlinux bs=8k
/etc/aboot.conf as its configuration file. Confirm that the file contains an image section with the same version as the kernel package just installed, and likewise for the initramfs image:
boot=/dev/sda1 init-message=Welcome to Fedora! Hit <TAB> for boot options partition=2 timeout=30 install=/usr/lib/yaboot/yaboot delay=10 nonvram image=/vmlinuz-2.6.32-17.EL label=old read-only initrd=/initramfs-2.6.32-17.EL.img append="root=LABEL=/" image=/vmlinuz-2.6.32-19.EL label=linux read-only initrd=/initramfs-2.6.32-19.EL.img append="root=LABEL=/"
default and set it to the label of the image stanza that contains the new kernel.
module-init-tools package is installed. Use these commands to determine if a module has been loaded successfully or when trying different modules for a piece of new hardware.
/sbin/lsmod displays a list of currently loaded modules. For example:
~]$ /sbin/lsmod
Module Size Used by
autofs4 25618 3
sunrpc 231823 1
bonding 115826 0
ip6t_REJECT 4641 2
nf_conntrack_ipv6 19623 2
ip6table_filter 2895 1
ip6_tables 19232 1 ip6table_filter
ipv6 322766 61 bonding,ip6t_REJECT,nf_conntrack_ipv6
dm_mirror 13723 0
dm_region_hash 11920 1 dm_mirror
dm_log 9944 2 dm_mirror,dm_region_hash
uinput 8126 0
sg 30478 0
sr_mod 16066 0
snd_ens1370 23085 4
gameport 10783 1 snd_ens1370
snd_rawmidi 22955 1 snd_ens1370
cdrom 39833 1 sr_mod
snd_seq 56461 0
snd_seq_device 6634 2 snd_rawmidi,snd_seq
snd_pcm 83399 1 snd_ens1370
snd_timer 22304 4 snd_seq,snd_pcm
snd 70077 12 snd_ens1370,snd_rawmidi,snd_seq,snd_seq_device,snd_pcm,snd_timer
virtio_net 15937 0
i2c_piix4 12707 0
soundcore 7892 1 snd
joydev 10514 0
snd_page_alloc 8604 2 snd_ens1370,snd_pcm
i2c_core 31338 1 i2c_piix4
virtio_balloon 3599 0
ext4 362885 2
mbcache 7510 1 ext4
jbd2 98427 1 ext4
virtio_blk 5159 3
ata_generic 3619 0
pata_acpi 3675 0
virtio_pci 6741 0
virtio_ring 6026 1 virtio_pci
virtio 4864 4 virtio_net,virtio_balloon,virtio_blk,virtio_pci
ata_piix 22532 0
dm_mod 73839 8 dm_mirror,dm_log
/sbin/lsmod command is less verbose and easier to read than the output of cat /proc/modules.
/sbin/modprobe command followed by the kernel module name. By default, modprobe attempts to load the module from the /lib/modules/<kernel-version>/kernel/drivers/ subdirectories. There is a subdirectory for each type of module, such as the net/ subdirectory for network interface drivers. Some kernel modules have module dependencies, meaning that other modules must be loaded first for it to load. The /sbin/modprobe command checks for these dependencies and loads the module dependencies before loading the specified module.
~]# /sbin/modprobe e100
e100 module before loading the e100 module itself.
/sbin/modprobe executes them, use the -v option. For example:
~]# /sbin/modprobe -v e100
/sbin/insmod /lib/modules/2.6.9-5.EL/kernel/drivers/net/e100.ko Using /lib/modules/2.6.9-5.EL/kernel/drivers/net/e100.ko Symbol version prefix 'smp_'
/sbin/insmod command can also be used to load kernel modules; however, it does not resolve dependencies. You should thus always use /sbin/modprobe instead of the insmod command to load kernel modules.
/sbin/rmmod command followed by the module name. The rmmod utility only unloads modules that are not in use and that are not a dependency of other modules in use.
~]# /sbin/rmmod e100
e100 kernel module.
modinfo. Use the command /sbin/modinfo to display information about a kernel module. The general syntax is:
~]# /sbin/modinfo [options] <kernel_module_name>
-d, which displays a brief description of the module, and -p, which lists the parameters the module supports. The modinfo command is useful for listing information such as version, dependencies, paramater options, and aliases of modules.For a complete list of options, refer to the modinfo man page.
/sbin/lsmod shows. You can specify other modules to be loaded at boot time by creating a file in the /etc/sysconfig/modules/ directory. You can use any name you like for the file that you create, but you must give it a .modules extension, and you must make it executable by running the following command:
modules]# chmod 755 <filename.modules>
bluez-uinput.modules that loads the uinput module:
#!/bin/sh
if [ ! -c /dev/input/uinput ] ; then
exec /sbin/modprobe uinput >/dev/null 2>&1
fi
.modules file should be a shebang line that gives the location of the bash shell interpreter:
#!/bin/sh
.modules files are bash scripts. The if-conditional on line 3 tests to make sure that the /dev/input/uinput files does not exist (the ! symbol negates the condition), and, if that is the case, then executes /sbin/modprobe with the name of the kernel module to load—uinput in this example. The remainder of the line simply redirects any output so that the modprobe command is quiet.
e100 driver with the e100_speed_duplex=4 option.
| Hardware | Module | Parameters |
|---|---|---|
| 3ware Storage Controller and 9000 series |
3w-xxxx.ko, 3w-9xxx.ko
| |
| Adaptec Advanced Raid Products, Dell PERC2, 2/Si, 3/Si, 3/Di, HP NetRAID-4M, IBM ServeRAID, and ICP SCSI driver |
aacraid.ko
|
nondasd — Control scanning of hba for nondasd devices. 0=off, 1=on
dacmode — Control whether dma addressing is using 64 bit DAC. 0=off, 1=on
commit — Control whether a COMMIT_CONFIG is issued to the adapter for foreign arrays. This is typically needed in systems that do not have a BIOS. 0=off, 1=on
startup_timeout — The duration of time in seconds to wait for adapter to have it's kernel up and running. This is typically adjusted for large systems that do not have a BIOS
aif_timeout — The duration of time in seconds to wait for applications to pick up AIFs before deregistering them. This is typically adjusted for heavily burdened systems.
numacb — Request a limit to the number of adapter control blocks (FIB) allocated. Valid values are 512 and down. Default is to use suggestion from Firmware.
acbsize — Request a specific adapter control block (FIB) size. Valid values are 512, 2048, 4096 and 8192. Default is to use suggestion from Firmware.
|
| Adaptec 28xx, R9xx, 39xx AHA-284x, AHA-29xx, AHA-394x, AHA-398x, AHA-274x, AHA-274xT, AHA-2842, AHA-2910B, AHA-2920C, AHA-2930/U/U2, AHA-2940/W/U/UW/AU/, U2W/U2/U2B/, U2BOEM, AHA-2944D/WD/UD/UWD, AHA-2950U2/W/B, AHA-3940/U/W/UW/, AUW/U2W/U2B, AHA-3950U2D, AHA-3985/U/W/UW, AIC-777x, AIC-785x, AIC-786x, AIC-787x, AIC-788x , AIC-789x, AIC-3860 |
aic7xxx.ko
|
verbose — Enable verbose/diagnostic logging
allow_memio — Allow device registers to be memory mapped
debug — Bitmask of debug values to enable
no_probe — Toggle EISA/VLB controller probing
probe_eisa_vl — Toggle EISA/VLB controller probing
no_reset — Supress initial bus resets
extended — Enable extended geometry on all controllers
periodic_otag — Send an ordered tagged transaction periodically to prevent tag starvation. This may be required by some older disk drives or RAID arrays.
tag_info:<tag_str> — Set per-target tag depth
global_tag_depth:<int> — Global tag depth for every target on every bus
seltime:<int> — Selection Timeout (0/256ms,1/128ms,2/64ms,3/32ms)
|
| IBM ServeRAID |
ips.ko
| |
| LSI Logic MegaRAID Mailbox Driver |
megaraid_mbox.ko
|
unconf_disks — Set to expose unconfigured disks to kernel (default=0)
busy_wait — Max wait for mailbox in microseconds if busy (default=10)
max_sectors — Maximum number of sectors per IO command (default=128)
cmd_per_lun — Maximum number of commands per logical unit (default=64)
fast_load — Faster loading of the driver, skips physical devices! (default=0)
debug_level — Debug level for driver (default=0)
|
| Emulex LightPulse Fibre Channel SCSI driver |
lpfc.ko
|
lpfc_poll — FCP ring polling mode control: 0 - none, 1 - poll with interrupts enabled 3 - poll and disable FCP ring interrupts
lpfc_log_verbose — Verbose logging bit-mask
lpfc_lun_queue_depth — Max number of FCP commands we can queue to a specific LUN
lpfc_hba_queue_depth — Max number of FCP commands we can queue to a lpfc HBA
lpfc_scan_down — Start scanning for devices from highest ALPA to lowest
lpfc_nodev_tmo — Seconds driver will hold I/O waiting for a device to come back
lpfc_topology — Select Fibre Channel topology
lpfc_link_speed — Select link speed
lpfc_fcp_class — Select Fibre Channel class of service for FCP sequences
lpfc_use_adisc — Use ADISC on rediscovery to authenticate FCP devices
lpfc_ack0 — Enable ACK0 support
lpfc_cr_delay — A count of milliseconds after which an interrupt response is generated
lpfc_cr_count — A count of I/O completions after which an interrupt response is generated
lpfc_multi_ring_support — Determines number of primary SLI rings to spread IOCB entries across
lpfc_fdmi_on — Enable FDMI support
lpfc_discovery_threads — Maximum number of ELS commands during discovery
lpfc_max_luns — Maximum allowed LUN
lpfc_poll_tmo — Milliseconds driver will wait between polling FCP ring
|
| HP Smart Array | cciss.ko | |
| LSI Logic MPT Fusion | mptbase.ko mptctl.ko mptfc.ko mptlan.ko mptsas.ko mptscsih.ko mptspi.ko |
mpt_msi_enable — MSI Support Enable
mptfc_dev_loss_tmo — Initial time the driver programs the transport to wait for an rport to return following a device loss event.
mpt_pt_clear — Clear persistency table
mpt_saf_te — Force enabling SEP Processor
|
| QLogic Fibre Channel Driver | qla2xxx.ko |
ql2xlogintimeout — Login timeout value in seconds.
qlport_down_retry — Maximum number of command retries to a port that returns a PORT-DOWN status
ql2xplogiabsentdevice — Option to enable PLOGI to devices that are not present after a Fabric scan.
ql2xloginretrycount — Specify an alternate value for the NVRAM login retry count.
ql2xallocfwdump — Option to enable allocation of memory for a firmware dump during HBA initialization. Default is 1 - allocate memory.
extended_error_logging — Option to enable extended error logging.
ql2xfdmienable — Enables FDMI registratons.
|
| NCR, Symbios and LSI 8xx and 1010 | sym53c8xx DEPRECATED |
cmd_per_lun — The maximum number of tags to use by default
tag_ctrl — More detailed control over tags per LUN
burst — Maximum burst. 0 to disable, 255 to read from registers
led — Set to 1 to enable LED support
diff — 0 for no differential mode, 1 for BIOS, 2 for always, 3 for not GPIO3
irqm — 0 for open drain, 1 to leave alone, 2 for totem pole
buschk — 0 to not check, 1 for detach on error, 2 for warn on error
hostid — The SCSI ID to use for the host adapters
verb — 0 for minimal verbosity, 1 for normal, 2 for excessive
debug — Set bits to enable debugging
settle — Settle delay in seconds. Default 3
nvram — Option currently not used
excl — List ioport addresses here to prevent controllers from being attached
safe — Set other settings to a "safe mode"
|
ethtool or mii-tool. Only after these tools fail to work should module parameters be adjusted. Module paramaters can be viewed using the modinfo command.
ethtool, mii-tool, and modinfo.
| Hardware | Module | Parameters |
|---|---|---|
| 3Com EtherLink PCI III/XL Vortex (3c590, 3c592, 3c595, 3c597) Boomerang (3c900, 3c905, 3c595) |
3c59x.ko
|
debug — 3c59x debug level (0-6)
options — 3c59x: Bits 0-3: media type, bit 4: bus mastering, bit 9: full duplex
global_options — 3c59x: same as options, but applies to all NICs if options is unset
full_duplex — 3c59x full duplex setting(s) (1)
global_full_duplex — 3c59x: same as full_duplex, but applies to all NICs if full_duplex is unset
hw_checksums — 3c59x Hardware checksum checking by adapter(s) (0-1)
flow_ctrl — 3c59x 802.3x flow control usage (PAUSE only) (0-1)
enable_wol — 3c59x: Turn on Wake-on-LAN for adapter(s) (0-1)
global_enable_wol — 3c59x: same as enable_wol, but applies to all NICs if enable_wol is unset
rx_copybreak — 3c59x copy breakpoint for copy-only-tiny-frames
max_interrupt_work — 3c59x maximum events handled per interrupt
compaq_ioaddr — 3c59x PCI I/O base address (Compaq BIOS problem workaround)
compaq_irq — 3c59x PCI IRQ number (Compaq BIOS problem workaround)
compaq_device_id — 3c59x PCI device ID (Compaq BIOS problem workaround)
watchdog — 3c59x transmit timeout in milliseconds
global_use_mmio — 3c59x: same as use_mmio, but applies to all NICs if options is unset
use_mmio — 3c59x: use memory-mapped PCI I/O resource (0-1)
|
| RTL8139, SMC EZ Card Fast Ethernet, RealTek cards using RTL8129, or RTL8139 Fast Ethernet chipsets |
8139too.ko
| |
| Broadcom 4400 10/100 PCI ethernet driver |
b44.ko
|
b44_debug — B44 bitmapped debugging message enable value
|
| Broadcom NetXtreme II BCM5706/5708 Driver |
bnx2.ko
|
disable_msi — Disable Message Signaled Interrupt (MSI)
|
| Intel Ether Express/100 driver |
e100.ko
|
debug — Debug level (0=none,...,16=all)
eeprom_bad_csum_allow — Allow bad eeprom checksums
|
| Intel EtherExpress/1000 Gigabit |
e1000.ko
|
TxDescriptors — Number of transmit descriptors
RxDescriptors — Number of receive descriptors
Speed — Speed setting
Duplex — Duplex setting
AutoNeg — Advertised auto-negotiation setting
FlowControl — Flow Control setting
XsumRX — Disable or enable Receive Checksum offload
TxIntDelay — Transmit Interrupt Delay
TxAbsIntDelay — Transmit Absolute Interrupt Delay
RxIntDelay — Receive Interrupt Delay
RxAbsIntDelay — Receive Absolute Interrupt Delay
InterruptThrottleRate — Interrupt Throttling Rate
SmartPowerDownEnable — Enable PHY smart power down
KumeranLockLoss — Enable Kumeran lock loss workaround
|
| Myricom 10G driver (10GbE) |
myri10ge.ko
|
myri10ge_fw_name — Firmware image name
myri10ge_ecrc_enable — Enable Extended CRC on PCI-E
myri10ge_max_intr_slots — Interrupt queue slots
myri10ge_small_bytes — Threshold of small packets
myri10ge_msi — Enable Message Signalled Interrupts
myri10ge_intr_coal_delay — Interrupt coalescing delay
myri10ge_flow_control — Pause parameter
myri10ge_deassert_wait — Wait when deasserting legacy interrupts
myri10ge_force_firmware — Force firmware to assume aligned completions
myri10ge_skb_cross_4k — Can a small skb cross a 4KB boundary?
myri10ge_initial_mtu — Initial MTU
myri10ge_napi_weight — Set NAPI weight
myri10ge_watchdog_timeout — Set watchdog timeout
myri10ge_max_irq_loops — Set stuck legacy IRQ detection threshold
|
| NatSemi DP83815 Fast Ethernet |
natsemi.ko
|
mtu — DP8381x MTU (all boards)
debug — DP8381x default debug level
rx_copybreak — DP8381x copy breakpoint for copy-only-tiny-frames
options — DP8381x: Bits 0-3: media type, bit 17: full duplex
full_duplex — DP8381x full duplex setting(s) (1)
|
| AMD PCnet32 and AMD PCnetPCI |
pcnet32.ko
| |
| PCnet32 and PCnetPCI |
pcnet32.ko
|
debug — pcnet32 debug level
max_interrupt_work — pcnet32 maximum events handled per interrupt
rx_copybreak — pcnet32 copy breakpoint for copy-only-tiny-frames
tx_start_pt — pcnet32 transmit start point (0-3)
pcnet32vlb — pcnet32 Vesa local bus (VLB) support (0/1)
options — pcnet32 initial option setting(s) (0-15)
full_duplex — pcnet32 full duplex setting(s) (1)
homepna — pcnet32 mode for 79C978 cards (1 for HomePNA, 0 for Ethernet, default Ethernet
|
| RealTek RTL-8169 Gigabit Ethernet driver |
r8169.ko
|
media — force phy operation. Deprecated by ethtool (8).
rx_copybreak — Copy breakpoint for copy-only-tiny-frames
use_dac — Enable PCI DAC. Unsafe on 32 bit PCI slot.
debug — Debug verbosity level (0=none, ..., 16=all)
|
| Neterion Xframe 10GbE Server Adapter |
s2io.ko
| |
| SIS 900/701G PCI Fast Ethernet |
sis900.ko
|
multicast_filter_limit — SiS 900/7016 maximum number of filtered multicast addresses
max_interrupt_work — SiS 900/7016 maximum events handled per interrupt
sis900_debug — SiS 900/7016 bitmapped debugging message level
|
| Adaptec Starfire Ethernet driver |
starfire.ko
|
max_interrupt_work — Maximum events handled per interrupt
mtu — MTU (all boards)
debug — Debug level (0-6)
rx_copybreak — Copy breakpoint for copy-only-tiny-frames
intr_latency — Maximum interrupt latency, in microseconds
small_frames — Maximum size of receive frames that bypass interrupt latency (0,64,128,256,512)
options — Deprecated: Bits 0-3: media type, bit 17: full duplex
full_duplex — Deprecated: Forced full-duplex setting (0/1)
enable_hw_cksum — Enable/disable hardware cksum support (0/1)
|
| Broadcom Tigon3 |
tg3.ko
|
tg3_debug — Tigon3 bitmapped debugging message enable value
|
| ThunderLAN PCI |
tlan.ko
|
aui — ThunderLAN use AUI port(s) (0-1)
duplex — ThunderLAN duplex setting(s) (0-default, 1-half, 2-full)
speed — ThunderLAN port speen setting(s) (0,10,100)
debug — ThunderLAN debug mask
bbuf — ThunderLAN use big buffer (0-1)
|
| Digital 21x4x Tulip PCI Ethernet cards SMC EtherPower 10 PCI(8432T/8432BT) SMC EtherPower 10/100 PCI(9332DST) DEC EtherWorks 100/10 PCI(DE500-XA) DEC EtherWorks 10 PCI(DE450) DEC QSILVER's, Znyx 312 etherarray Allied Telesis LA100PCI-T Danpex EN-9400, Cogent EM110 |
tulip.ko
|
io io_port
|
| VIA Rhine PCI Fast Ethernet cards with either the VIA VT86c100A Rhine-II PCI or 3043 Rhine-I D-Link DFE-930-TX PCI 10/100 |
via-rhine.ko
|
max_interrupt_work — VIA Rhine maximum events handled per interrupt
debug — VIA Rhine debug level (0-7)
rx_copybreak — VIA Rhine copy breakpoint for copy-only-tiny-frames
avoid_D3 — Avoid power state D3 (work-around for broken BIOSes)
|
alias and, possibly, options lines for each card in a user-created <module_name>.conf/etc/modprobe.d/ directory.
bonding kernel module and a special network interface, called a channel bonding interface. Channel bonding enables two or more network interfaces to act as one, simultaneously increasing the bandwidth and providing redundancy.
/etc/modprobe.conf:
alias bond<N> bonding
<N> with the interface number, such as 0. For each configured channel bonding interface, there must be a corresponding entry in /etc/modprobe.conf.
miimon or arp_interval and the arp_ip_target parameters. Refer to Section 29.5.2.1, “bonding Module Directives” for a list of available options and how to quickly determine the best ones for your bonded interface.
BONDING_OPTS="<bonding parameters>" directive in your bonding interface configuration file (ifcfg-bond0 for example). Parameters to bonded interfaces can be configured without unloading (and reloading) the bonding module by manipulating files in the sysfs file system.
sysfs is a virtual file system that represents kernel objects as directories, files and symbolic links. sysfs can be used to query for information about kernel objects, and can also manipulate those objects through the use of normal file system commands. The sysfs virtual file system has a line in /etc/fstab, and is mounted under /sys.
/sys/class/net/ directory. After you have created a channel bonding interface file such as ifcfg-bond0 and inserted SLAVE=bond0 directives in the bonded interfaces following the instructions in Section 4.2.2, “Channel Bonding Interfaces”, you can then proceed to testing and determining the best parameters for your bonded interface.
ifconfig bond<N> up as root:
~]# ifconfig bond0 up
ifcfg-bond0 bonding interface file, you will be able to see bond0 listed in the output of running ifconfig (without any options):
~]# ifconfig
bond0 Link encap:Ethernet HWaddr 00:00:00:00:00:00
UP BROADCAST RUNNING MASTER MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
eth0 Link encap:Ethernet HWaddr 52:54:00:26:9E:F1
inet addr:192.168.122.251 Bcast:192.168.122.255 Mask:255.255.255.0
inet6 addr: fe80::5054:ff:fe26:9ef1/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:207 errors:0 dropped:0 overruns:0 frame:0
TX packets:205 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:70374 (68.7 KiB) TX bytes:25298 (24.7 KiB)
[output truncated]
~]# cat /sys/class/net/bonding_masters bond0
/sys/class/net/bond<N>/bonding/ directory. First, the bond you are configuring must be taken down:
~]# ifconfig bond0 down
~]# echo 1000 > /sys/class/net/bond0/bonding/miimon
balance-alb mode, you could run either:
~]# echo 6 > /sys/class/net/bond0/bonding/mode
~]# echo balance-alb > /sys/class/net/bond0/bonding/mode
ifconfig bond<N> up . If you decide to change the options, take the interface down, modify its parameters using sysfs, bring it back up, and re-test.
BONDING_OPTS= directive of the /etc/sysconfig/network-scripts/ifcfg-bond<N> file for the bonded interface you are configuring. Whenever that bond is brought up (for example, by the system during the boot sequence if the ONBOOT=yes directive is set), the bonding options specified in the BONDING_OPTS will take effect for that bond. For more information on configuring bonded interfaces (and BONDING_OPTS), refer to Section 4.2.2, “Channel Bonding Interfaces”.
bonding module. For more in-depth information on configuring channel bonding and the exhaustive list of bonding module parameters, install the kernel-doc package (refer to Section 29.6, “Additional Resources”) and then locate and reference the bonding.txt file:
~]# yum -y install kernel-doc ~]# gedit $(rpm -ql kernel-doc |grep -i bonding.txt) &
arp_interval=<time_in_milliseconds> arp_interval and arp_ip_target parameters are specified, or, alternatively, the miimon parameter is specified. Failure to do so can cause degradation of network performance in the event that a link fails.
mode=0 or mode=1 (the two load-balancing modes), the network switch must be configured to distribute packets evenly across the NICs. For more information on how to accomplish this, refer to /usr/share/doc/kernel-doc-<kernel_version>/Documentation/networking/bonding.txt
0 by default, which disables it.
arp_ip_target=<ip_address> [,<ip_address_2>,...<ip_address_16> ] arp_interval parameter is enabled. Up to 16 IP addresses can be specified in a comma separated list.
arp_validate=<value> none. Other valid values are active, backup, and all.
debug=<number> 0 — Debug messages are disabled. This is the default.
1 — Debug messages are enabled.
downdelay=<time_in_milliseconds> miimon parameter. The value is set to 0 by default, which disables it.
<value> slow or 0 — Default setting. This specifies that partners should transmit LACPDUs every 30 seconds.
fast or 1 — Specifies that partners should transmit LACPDUs every 1 second.
miimon=<time_in_milliseconds> ~]# ethtool <interface_name> | grep "Link detected:"
<interface_name> with the name of the device interface, such as eth0, not the bond interface. If MII is supported, the command returns:
Link detected: yes
0 (the default), turns this feature off. When configuring this setting, a good starting point for this parameter is 100.
arp_interval and arp_ip_target parameters are specified, or, alternatively, the miimon parameter is specified. Failure to do so can cause degradation of network performance in the event that a link fails.
mode=<value> <value> is one of:
balance-rr or 0 — Sets a round-robin policy for fault tolerance and load balancing. Transmissions are received and sent out sequentially on each bonded slave interface beginning with the first one available.
active-backup or 1 — Sets an active-backup policy for fault tolerance. Transmissions are received and sent out via the first available bonded slave interface. Another bonded slave interface is only used if the active bonded slave interface fails.
balance-xor or 2 — Sets an XOR (exclusive-or) policy for fault tolerance and load balancing. Using this method, the interface matches up the incoming request's MAC address with the MAC address for one of the slave NICs. Once this link is established, transmissions are sent out sequentially beginning with the first available interface.
broadcast or 3 — Sets a broadcast policy for fault tolerance. All transmissions are sent on all slave interfaces.
802.3ad or 4 — Sets an IEEE 802.3ad dynamic link aggregation policy. Creates aggregation groups that share the same speed and duplex settings. Transmits and receives on all slaves in the active aggregator. Requires a switch that is 802.3ad compliant.
balance-tlb or 5 — Sets a Transmit Load Balancing (TLB) policy for fault tolerance and load balancing. The outgoing traffic is distributed according to the current load on each slave interface. Incoming traffic is received by the current slave. If the receiving slave fails, another slave takes over the MAC address of the failed slave.
balance-alb or 6 — Sets an Active Load Balancing (ALB) policy for fault tolerance and load balancing. Includes transmit and receive load balancing for IPV4 traffic. Receive load balancing is achieved through ARP negotiation.
num_unsol_na=<number> 0 - 255; the default value is 1. This option affects only the active-backup mode.
primary=<interface_name> eth0, of the primary device. The primary device is the first of the bonding interfaces to be used and is not abandoned unless it fails. This setting is particularly useful when one NIC in the bonding interface is faster and, therefore, able to handle a bigger load.
active-backup mode. Refer to /usr/share/doc/kernel-doc-<kernel-version>/Documentation/networking/bonding.txt for more information.
primary_reselect=<value> always or 0 (default) — The primary slave becomes the active slave whenever it comes back up.
better or 1 — The primary slave becomes the active slave when it comes back up, if the speed and duplex of the primary slave is better than the speed and duplex of the current active slave.
failure or 2 — The primary slave becomes the active slave only if the current active slave fails and the primary slave is up.
primary_reselect setting is ignored in two cases:
primary_reselect policy via sysfs will cause an immediate selection of the best active slave according to the new policy. This may or may not result in a change of the active slave, depending upon the circumstances
updelay=<time_in_milliseconds> miimon parameter. The value is set to 0 by default, which disables it.
use_carrier=<number> miimon should use MII/ETHTOOL ioctls or netif_carrier_ok() to determine the link state. The netif_carrier_ok() function relies on the device driver to maintains its state with netif_carrier_on/off ; most device drivers support this function.
netif_carrier_on/off .
1 — Default setting. Enables the use of netif_carrier_ok().
0 — Enables the use of MII/ETHTOOL ioctls.
netif_carrier_on/off .
xmit_hash_policy=<value> balance-xor and 802.3ad modes. Possible values are:
0 or layer2 — Default setting. This option uses the XOR of hardware MAC addresses to generate the hash. The formula used is:
(<source_MAC_address>XOR<destination_MAC>) MODULO<slave_count>
1 or layer3+4 — Uses upper layer protocol information (when available) to generate the hash. This allows for traffic to a particular network peer to span multiple slaves, although a single connection will not span multiple slaves.
((<source_port>XOR<dest_port>) XOR ((<source_IP>XOR<dest_IP>) AND0xffff) MODULO<slave_count>
layer2 transmit hash policy.
2 or layer2+3 — Uses a combination of layer2 and layer3 protocol information to generate the hash.
(((<source_IP>XOR<dest_IP>) AND0xffff) XOR (<source_MAC>XOR<destination_MAC>)) MODULO<slave_count>
lsmod, modprobe, mmod, modinfo — Refer to the man pages for these commands to learn how to display module information and manipulate modules.
~]# yum install kernel-doc
/usr/share/doc/kernel-doc-<kernel_version>/Documentation.
[9] A driver is software which enables Linux to use a particular hardware device. Without a driver, the kernel cannot communicate with attached devices.
| Revision History | |||
|---|---|---|---|
| Revision 1 | Mon Nov 16 2009 | ||
| |||