Red Hat ENTERPRISE LINUX 5 - DEPLOYMENT Deployment Manual page 417

Even if a user does not plan to send email from the system, some automated tasks or system
programs might use the /bin/mail command to send email containing log messages to the root user
of the local system.
Red Hat Enterprise Linux 5 provides three MTAs: Sendmail, Postfix, and Exim. If all three are
installed, sendmail is the default MTA. The Mail Transport Agent Switcher allows for the selection
of either sendmail, postfix, or exim as the default MTA for the system.
The system-switch-mail RPM package must be installed to use the text-based version of the Mail
Transport Agent Switcher program. If you want to use the graphical version, the system-switch-
mail-gnome package must also be installed.
Note
For more information on installing RPM packages, refer to
Management".
To start the Mail Transport Agent Switcher, select System (the main menu on the panel) >
Administration > Mail Transport Agent Switcher, or type the command system-switch-mail at
a shell prompt (for example, in an XTerm or GNOME terminal).
The program automatically detects if the X Window System is running. If it is running, the program
starts in graphical mode as shown in
detected, it starts in text-mode. To force Mail Transport Agent Switcher to run in text-mode, use the
command system-switch-mail-nox.
Figure 24.1. Mail Transport Agent Switcher
If you select OK to change the MTA, the selected mail daemon is enabled to start at boot time, and
the unselected mail daemons are disabled so that they do not start at boot time. The selected mail
Figure 24.1, "Mail Transport Agent
Mail Transport Agent (MTA) Configuration
Part II, "Package
Switcher". If X is not
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