Mayur's BLOG

Additional SMTP Port Plesk Linux

Choose any unused port and add it to the /etc/services file, for example:

smtp2 26/udp mail
smtp2 26/tcp mail

Copy /etc/xinetd.d/smtp_psa to smtp2_psa

In the new file, REPLACE 'service smtp' WITH 'service smtp2'

Then restart xinetd
/etc/init.d/xinetd restart

Check that the new port is now listening
# netstat -plunt |grep :26

That should return something similar to

tcp 0 0 0.0.0.0:26 0.0.0.0:* LISTEN 2345/xinetd

Test connection by telnetting from an outside box to port 26 on the server:
telnet 123.123.123.123 26