Chapter 21. Mail Transport Agent (MTA) Configuration
A Mail Transport Agent (MTA) is essential for
sending email from a Red Hat Linux system. The Mail User
Agent (MUA) such as Mozilla Mail,
Mutt, Pine, and
Evolution is used to read and compose
email. When a user sends an email from an MUA, the messages are handed off
to the MTA, which sends the message to a series of MTAs until it reaches
its destination.
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 Linux 8.0 provides two MTAs: Sendmail and Postfix. If both are
installed, sendmail is the default
MTA. Mail Transport Agent Switcher allows
a user to select either sendmail or
postfix as the default MTA for the system.
To start the Mail Transport Agent Switcher, select (on the Panel) => =>
=> , or type the command
redhat-switchmail at a shell prompt (for example, in an
XTerm or GNOME terminal).
The program automatically detect if the X Window System is running. If it
is running, the program starts in graphical mode as shown in Figure 21-1. If X is not detected, it starts in
text-mode. To force Mail Transport Agent Switcher to run in
text-mode, use the command redhat-switchmail-nox.
If you selected Postfix, you must make sure the
sendmail service is stopped and the
postfix service is started:
/sbin/service sendmail stop
/sbin/service postfix start |
If you selected Sendmail, you must make sure the
postfix service is stopped and the
sendmail service is started:
/sbin/service postfix stop
/sbin/service sendmail start |
To enable or disable the services at boot time, you must configure the
runlevel with Services Configuration Tool,
ntsysv, or
chkconfig. Refer to Chapter 13 for details.
For more information about email protocols and MTAs, refer to the
Official Red Hat Linux Reference Guide.
