PMTA How to change SMTP port in PowerMTA

[Underground Forum]

SMTP port in pmta config​

To change the SMTP port in PMTA, find and edit the config file at /etc/pmta/config

Find the line that starts with smtp-listener
This line specifies the port used by the PMTA server. If you need to use several ports, duplicate the line.

smtp-listener 0/0:2424
smtp-listener 0/0:25

This change will force PMTA to use ports 25 and 2424 at the same time.