Using Graphical Tools to Configure Network Interfaces
The procedures described so far show how network interfaces are configured from scratch from the command line. When a Linux system starts, you seldom have to issue these commands, because the startup scripts for the Linux system distribution will execute them in the startup scripts. These startup scripts are shell (bash, actually which is the Born Again Shell) scripts, and differ from distribution to distribution. Some distributions use the BSD UNIX-style startup scripts (such as Slackware) whereas others use the System VR4 UNIX-style startup scripts (such as RedHat). The details of the startup script change from distribution to distribution. Even within the same distribution, different versions of the distribution sometimes make radical changes in their startup scripts.
However, many distributions come with a graphical tool to simplify network configuration. These tools will automatically make changes so that your Linux system startup scripts will find the appropriate TCP/IP parameters.
One of the first graphical tools for configuring Linux is netcfg. Simply run netcfg from the command line to start it, and explore its structure. Figure 28.4 shows the netcfg starting menu. The netcfg tool can be used to configure names, hosts, interfaces, and routing.
Figure 28.4 The GUI tool netcfg.
Another very powerful tool is linuxconf, which can be used to configure networking and perform most system administration tasks. This is a worthwhile tool to master because it can quickly perform both routine and complex tasks. Simply run linuxconf from the command line. Your X-Windows Desktop Manager such as KDE or GNOME may already have linuxconf in one of the program groups, in which case you can select it with a mouse and run the program. Figure 28.5 shows the starting screen of linuxconf.
Figure 28.5 The GUI tool linuxconf.
To change host names, expand the directory tree by making the selections Config, Networking, Client Tasks, Basic host information (see Figure 28.6).
Figure 28.6 Linuxconf - Basic Host Configuration.
To configure the name resolver, expand the directory tree by making the selections Config, Networking, Client Tasks, Name server specification (DNS) (see Figure 28.7).
Figure 28.7 Linuxconf Configuring name resolver. ***To configure host routing, expand the directory tree by making the selections Config, Networking, Client Tasks, Routing and gateways, Set Defaults (see Figure 28.8).
Figure 28.8 Linuxconf - Configuring default router.
To configure the order of name resolution, expand the directory tree by making the selections Config, Networking, Client Tasks, Host name search path (see Figure 28.9).
Figure 28.9 Linuxconf - Host name search path.
You can even configure BIND if you expand the directory tree by selecting Config, Networking, Server Tasks, Domain Name Server (DNS, Config (see Figure 28.10). You can configure domains, IP reverse mappings, secondaries, forward zones, features, and IP allocation space. However, if you are serious about learning to configure BIND, you should learn the syntax of the BIND startup file (/etc/named.boot for BIND 4 and /etc/named.conf for BIND 8 and 9), and the syntax of the zone data files, and learn to edit these files directly.
Figure 28.10 Linuxconf - Configuring BIND.