Red Hat uses a number of small configuration tools, most of which are accessible from the Server Settings, System Settings, and System Tools menu off of the GNOME Applications menu, as shown in Figure 9.4. These tools are also accessible from the Start Here icon on the default Red Hat desktop. Each of these tools provides a way to configure a specific feature, such as the network or sound card. (Figure 9.2 shows Red Hat's sound card detection tool.) If you log in as an ordinary user but need to administer the system, you can do so, but the tool will ask for the root password when you select it. The system remembers the password for a while, so calling other configuration tools soon after the first won't result in a new root password prompt.

Figure 9.4: Red Hat makes its administrative tools accessible from menus on its default desktop configuration.

Red Hat's startup procedure and configuration file locations are quite similar to those of Mandrake. This fact shouldn't be surprising because Mandrake used Red Hat as its starting point and, as a result, the two distributions share a common heritage. With every new release, though, Red Hat and Mandrake deviate more. Some of the important configuration files in Red Hat include:

System Startup Procedure Red Hat's /etc/inittab calls

/etc/rc.d/rc.sysinit as the system initialization script. This script performs a large number of basic initialization tasks, such as mounting the device filesystem, setting the system clock, and so on. Red Hat's init then switches to the runlevel specified in /etc/inittab and runs the startup scripts in the appropriate SysV startup script directory by calling /etc/rc.d/rc.

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

Runlevels and Starting X Red Hat uses a line in /etc/inittab to start an XDMCP server, and hence X, in runlevel 5. This line calls /etc/X11/prefdm, which reads /etc/sysconfig/desktop and uses the variable DISPLAYMANAGER to determine which XDMCP server to run.

cron Red Hat's default cron configuration includes an /etc/crontab file that calls files in the /etc/cron.interval directories, where interval is hourly, daily, weekly, or monthly. Except for the hourly run, these scripts run between 4:02 a.m. and 4:42 a.m.

Super Server Red Hat usesxinetd by default. The/etc/xinetd.conf file is the master configuration file, while /etc/xinetd.d holds files for specific servers xinetd is to handle.

Mail Server Red Hat ships with sendmail as the default mail server. It's administered through files in /etc/mail.

Network Configuration Red Hat uses the /etc/rc.d/init.d/network SysV startup script to start basic networking features. This script relies on variables stored in the /etc/sysconfig/network file and files in the /etc/sysconfig/networking and /etc/sysconfig/network-scripts directories. Therefore, you must edit these files to permanently change some networking details.

Local Startup Files If you want to change something about the system configuration that doesn't fit in well in the default script set, you can edit the /etc/rc.d/rc.local script. This script executes after the conventional

SysV startup scripts.

For the most part, bypassing Red Hat's default or GUI-created configurations poses no special challenges; just edit the relevant configuration files by hand. If you accidentally launch a GUI configuration tool, select Cancel or another appropriate option to quit without saving the changes.

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