Advanced sendmail configuration

Most sendmail configuration is accomplished by editing the configuration file, /usr/lib/sendmail.cf. The syntax of this file is designed to be reasonably easy to parse, because this is done every time sendmail starts up. As a result, the configuration file is not particularly easy for a human to read or write.

The configuration file has three major purposes:

• setting up the environment for sendmail

• rewriting addresses in the message

• mapping addresses into the set of instructions that will deliver the message

This section provides an overview of the standard configuration file built with the mkdev cf script, provides the specifications for configuration file lines, and describes building a configuration file from scratch.