Episode 20: How can I redirect mail to a different port on my smarthost?

If a system administrator does not want to use the default port 25 for SMTP traffic to a smarthost, it can be redirected by inserting this line into the sendmail.mc file to change the port number:

define(`RELAY_MAILER_ARGS', `TPC $h XXXX')dnl


Replace XXXX with the desired port on the smarthost. The Sendmail service must be restarted after applying this change. Restart the service with:

service sendmail restart


Note: If for any reason, a restart of the mail server has to be avoided, the sendmail service can be reloaded instead by issuing the command:

service sendmail reload