Chapter 23. Mail Transport Agent (MTA) Configuration

A Mail Transport Agent (MTA) is essential for sending email from a Red Hat Linux system. A Mail User Agent (MUA) such as Evolution, Mozilla Mail, and Mutt 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 9 provides two MTAs: Sendmail and Postfix. If both are installed, sendmail is the default MTA. The Mail Transport Agent Switcher allows for the selection of either sendmail or postfix as the default MTA for the system.

The redhat-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 redhat-switch-mail-gnome package must also be installed. For more information on installing RPM packages, refer to Part V Package Management.

To start the Mail Transport Agent Switcher, select Main Menu Button (on the Panel) => System Tools => More System Tools => Mail Transport Agent Switcher, or type the command redhat-switch-mail at a shell prompt (for example, in an XTerm or GNOME terminal).

Figure 23-1. 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-switch-mail-nox.

If you select OK daemon is started, and the other mail daemon is stopped; thus making the changes take place immediately.

For more information about email protocols and MTAs, refer to the Red Hat Linux Reference Guide. For more information about MUAs, refer to the Red Hat Linux Getting Started Guide.