Debian

As mentioned previously, site and module configurations and options are placed in the sites-available and mods -available directories. They are not included unless there is a link to them in the sites-enabled or mods-enabled directory. Instead of making the links manually, use the a2enmod and a2dismod commands to enable or disable modules, and the a2ensite and a2dissite commands to enable or disable specific site configurations.

The basic configuration file layout is as follows and is also documented in the /etc/apache2/apache2.conf:

/etc/apache21 1--apache2 .conf

1 ' --ports .conf 1--mods-enabled 1 1--'.load

1 ' --". conf 1--conf .d

! . sites-enabled

Here we will look at the Apache web server software configuration and see how Debian handles it. The details on what the configuration actually does will not be covered, as they are complex and covered in the package documentation. However, we will look at how the files are set up, and what procedures are provided by Debian for configuration maintenance.

So, how do you know what configuration facilities are provided and what the recommended approach to local configuration is? The best place to begin is the README. debian file that comes with the package. Itis a requirement of the Debian Policy manual that this file explains any special configuration issues, how configuration under Debian differs from the configuration provisions of the original software developers, and recommended ways to handle local configuration. It also explains any utilities Debian has added to aid in the software configuration.

Many software packages not only support separate, local configuration files, but also provide a special subdirectory to help organize and manage multiple configuration files. In some cases, the files in these directories require a specific extension in order to be considered active or enabled. lbis makes it easy to enable or disable software features. In other cases, all files in the directory are considered as part of the configuration, and a different method is used to enable and disable specific files or features, such as used in the Debian Apache software packages.

Many software packages are moving to a multiple file configuration system. Debian developers are using this feature to protect local changes by instructing administrators to place their modifications in a file with a . local extension. In other cases, such as the Apache configuration directories, files are placed in specified subdirectories (conf.d and sites-available in this case), and may be named freely, as long as they don't conflict with file names used by standard Debian or upstream configurations.

Because Debian upgrades often affect configuration files, the developers have crafted techniques to lower the impact of upgrades on locally modified configurations. In particular, they are moving to provide separate local configuration files and special directories that help maintain local changes during upgrades.

Finally, there are a number of packages that were created for the express purpose of configuring individual services. There are software packages that provide graphic or command line configuration tools for any number of other software packages. The packages vary in complexity and usage, as they are usually provided by third parties. They can be found by using any of the search capable Debian package managers. Synaptic is probably the easiest as it allows one to easily browse descriptions after searching.

So far, we have been discussing server configuration. User configuration of a desktop environment is actually a little easier, as both GNOME (GNU Object Model Environment) and KDE (K Desktop Environment), as well as other desktop managers, provide a full suite of utilities gathered in one menu area that allows the user to easily configure things such as desktop appearance, behavior, window themes, login behavior, and system and session services relevant to their environment.

This is actually a suite of packages, each covering a different major service. Unfortunately, this is not as universal as dpkg-reconfigure, but it does handle more complex configurations. The following services are covered as of Debian 7:

• Bind (DNS)
• OpenVPN (both client and server)
• ProFTPD (FTP)
• RSYNC
• Samba (Windows Shares)

It is a graphical tool, based on GTK (GIMP Tool Kit). It was developed to provide some administrator functions under the GNOME desktop environment. It will handle fairly complex configurations.