Debian

Debian tends to shun specialized system administration tools. The Debian installer, of course, places a set of default configuration files in /etc, and some packages come with scripts that ask questions to help tune a configuration for your system. You can also use configuration tools that ship with or are written for specific packages, such as SWAT; or more general tools, such as Linuxconf

(http://www.solucorp.qc.ca/linuxconf/) or Webmin (http://www.webmin.com). In general, though, when you administer Debian you do so by directly editing the relevant configuration files; there is, therefore, no need to bypass any automatic configuration tool that might try to modify your changes itself.

Note Commercial Debian derivatives, such as Libranet (http://www.libranet.com) and Xandros (http://www.xandros.com), generally include more in the way of GUI administrative tools that may modify configuration files.

Of course, Debian has its own unique configuration quirks. Some of Debian's notable features that differ from some or all other Linux distributions include:

System Startup Procedure Debian's/etc/inittab calls/etc/init.d/rcS as the system initialization script. This script calls the startup scripts in /etc/rcS.d and any scripts in /etc/rc.boot (the latter is intended for local startup scripts, but its use is officially discouraged). Debian's init then switches to the runlevel specified in /etc/inittab and runs /etc/init.d/rc, which runs the startup scripts in the appropriate SysV startup script directory.

Location of SysV Startup Scripts Debian places its SysV startup scripts in /etc/init.d and places links to these files for specific runlevels in /etc/rc?.d, where ? is the runlevel number.

Runlevels and Starting X There are few differences between runlevels 3-5 in Debian, except that runlevels above 3 provide just one text-mode virtual terminal. Instead of using a runlevel as a code for whether or not to start X and present an X Display Manager Control Protocol (XDMCP) GUI login screen, Debian uses SysV startup scripts for each of the major display managers. You can set which to start by default in the /etc/X11/default-display-manager file.

cron Debian's default cron configuration includes an /etc/crontab file that calls files in the /etc/cron.interval directories, where interval is daily, weekly, or monthly, at the stated intervals, and between 6:25 a.m. and 6:52 a.m.

Super Server Debian uses inetd by default, although xinetd is also available.

Mail Server Debian is the only major Linux distribution to use Exim as its default mail server. It's configured through /etc/exim/exim.conf. When you install Exim, the Debian package tools run a script that asks some basic questions to set up an initial Exim configuration.

Modules One of Debian's few deviations from the automatic configuration rule is that it uses a tool called update-modules to create an /etc/modules.conf file. This tool assembles files it finds in the /etc/modutils directory tree into/etc/modules.conf. The easiest way to deal with this system is to change the files in /etc/modutils or add new files to it, rather than directly editing /etc/modules.conf. Consult the update-modules man page for more details.

Network Configuration Debian uses the /etc/init.d/networking SysV

startup script to start basic networking features. This script relies on variables stored in files in the /etc/network directory tree. Therefore, permanently changing some networking details requires editing these files.

Local Startup Files If you want to change something about the system configuration that doesn't fit well in the default script set, you can create a script and place it in the /etc/rc.boot directory. Debian executes scripts in this directory after running the /etc/rcS.d scripts but before running the scripts for the startup runlevel. Debian's official documentation suggests creating SysV startup scripts and placing them in /etc/rcS.d or another SysV startup script directory, though.

As a general rule, Debian's configuration files are straightforward to adjust if you're used to text-based configuration. The SysV startup scripts work as they do on most Linux distributions. Local startup files are a bit odd if you're used to Red Hat, Mandrake, or SuSE; however, once you put a local startup script in /etc/rc.boot, you can modify it as you like.

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