Mailer tables are a simple way of directing messages to different Mail Delivery Agents (MDAs) on the basis of host or domain names. For example, consider this input file (e.g., /etc/mailertable ):
remote.foo.com uucp-uudom:home .skunkworks.foo.com relay:secret.foo.com
Here the first line says that anything addressed to email@example.com should be sent using the uucp-uudom deilvery agent to the host named home . The second line says that any message addressed to any host within the domain .skunkworks.foo.com should be sent using the relay delivery agent to the host secret.foo.com .
You can build the database from the input file using the % makemap (1) program:
You declare the database for use with your .mc file, like this:
FEATURE(mailertable, hash /etc/mailertable )