How to change Postfix default smtp port to 2525


By default Postfix listens on Port 25. You can change it to any port. In our case, we would want to change it to 2525.

vi /etc/postfix/


smtp inet n - n - - smtpd


2525 inet n - n - - smtpd

Restart Postfix service.

systemctl restart postfix.service


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