Change SMTP port in PowerMTA

To change SMTP port in PowerMTA, edit file

vi /etc/pmta/config

Find line starting with

smtp-listener

This line specify port used by PowerMTA server. You can change the power on this line. If you need PowerMTA listen to multiple ports, duplicate the line and change port, this will make PowerMTA work using both ports.

smtp-listener 0/0:2525
smtp-listener 0/0:25

This will make PowerMTA work on both port 25 and port 2525

After editing /etc/pmta/config, you need to restart PowerMTA with

systemctl restart pmta

See PowerMTA