Certification Objective 3.07-System Configuration Files

Red Hat sets up a number of key configuration files in the /etc/sysconfig directory. You can configure them with a text editor, with text commands, or in many cases with a Red Hat graphical tool. Many of the non-network system configuration files are discussed in this section.

It's fastest if you know how to configure these systems directly using text commands or by directly editing the key configuration file. However, if you forget how to manage one or two configuration commands or files, the Red Hat graphical tools can be a lifesaver.

I address only those systems not already covered in other chapters.

Non-network /etc/sysconfig Files

Let's return to the /etc/sysconfig directory and discuss some of the non-network configuration files listed in Table 3-3. This section covers only those files that are less likely to be of interest on the Red Hat exams. More important files are covered in other chapters. Some files can be edited directly; others can be configured with other Red Hat tools discussed in the following section.

Table 3-3: Key Non-network /etc/sysconfig Files

File in the /etc/sysconfig Directory	Description
clock	Contains defaults for the system clock, including time zone, UTC, and ARC (Alpha CPU-based) settings. If UTC=true, the BIOS is set to the atomic realization of Greenwich Mean Time.
firstboot	If RUN_FIRSTBOOT=YES, then you can start the First Boot process with the firstboot command, if you're in runlevel 5.
grub	Lists the hard disk with your /boot drive, assuming you're using the GRUB boot loader.
hwconf	Lists peripherals detected by kudzu. Do not edit this file!
i18n	Sets the default language.
init	Specifies the graphics and associated colors during the boot process.
iptables	Includes the iptables firewall commands that run when you boot Linux.
iptables-config	Adds configuration for adding iptables rules.
irda	Controls infrared devices.
kernel	Specifies defaults when you update the kernel.
keyboard	Contains keyboard configuration data: KEYBOARDTYPE, usually pc, and KEYTABLE, usually us.
kudzu	Configures hardware detection during the boot process, as it relates to serial ports, DDC (Display Data Channel) between the monitor and video card, and PS/2 ports.
ntpd	Specifies synchronization with the hardware clock after synchronizing with a remote NTP (network time protocol) server.
pcmcia	Contains PCMCIA configuration data. If PCMCIA=yes, Linux loads PCMCIA modules on boot.
pm	Configures hibernation characteristics.
rhn/	Directory with Red Hat Network configuration.

GUI Configuration Utilities

It's important to know how to configure RHEL 5 by hand, because it's the most efficient way to control everything on your Linux system. It's faster on the Red Hat exams, where time is of the essence. There are a number of good GUI configuration tools available; almost all of them are "front ends" that edit text configuration files, which you could edit directly.

However, there's a lot to learn about Linux. Learning how to edit all key Linux configuration files can be more than some RHCT/RHCE candidates can handle. While you should learn how to edit these files by hand, you may not have time. You may get nervous during the Red Hat exams and forget details. In these cases, the Red Hat GUI tools can be a lifesaver.

On the Job 

The text mode setup tool is a front end to a number of other tools you can view from the text console: authentication, firewall, keyboard, network, printer, service, time zone, and GUI display configuration. You can start the tool with the setup command. While they may be faster than GUI tools, some of these tools do not have the same capabilities as GUI tools.

Date/Time Properties

With the Date/Time Properties configuration tool, you can set the date, time, timezone, and NTP server for your system. You can start it in one of three ways in the GUI: run the system-config-date or system-config-time command, or choose System | Administration | Date and Time. This opens the Date/Time Properties window shown in Figure 3-8.

Figure 3-8: The Date/Time Properties window

Keyboard Configuration Tool

The Keyboard Configuration tool allows you to reselect the keyboard associated with your system. You can start it in one of two ways in the GUI: run the system-config-keyboard command or choose System | Administration | Keyboard. The options are the same as those you saw during the installation process. Results are recorded in /etc/sysconfig/keyboard.

Exam Watch

If you're studying for the RHCE, Red Hat has just added NTP configuration and troubleshooting to the Exam Prep guide. For more information, see Chapter 13.