Some services in Red Hat Linux can be implemented by several different software packages. Although you can, you probably don't want to run multiple mail and print servers on the same computer. At the very least, you should set the software you want to use by default.
In Red Hat Linux, an "alternatives" feature is packaged into the operating system. Alternatives is an implementation of the Debian GNU/Linux alternatives feature. In essence, alternatives links the software you choose (or leave by default) into the common locations where the service being implemented is launched or made available.
See the "Choosing Software Alternatives" section in Chapter 10 for further information on the alternatives feature.
The first services to be implemented under alternatives in Red Hat Linux are print and mail server packages. However, if the concept catches on, you can expect other kinds of services later. For now, graphical applications enable you to switch those two services:
Switching mail servers ( From the main Red Hat menu, select System Tools? More System Tools ? Mail Transport Agent Switcher (or type redhat-switch-mail from a Terminal window). The window that appears enables you to choose between the Sendmail (default) and Postfix mail-transport agents.
Switching print servers ( From the main Red Hat menu, select System Settings ?More System Settings ? Printer System Switcher (or type redhat-switch-printer from a Terminal window). Choose between the LPRng or CUPS (default) printing services.
Figure C-1 shows an example of the redhat-switch-mail window.