Creating additional SMTP port in Plesk
Normally SMTP port in plesk uses port 25 for mail access.
If required you can switch the SMTP port to an alternative port . For this you can use the following steps.
1) Login to the server as root.
2) Open the file /etc/services to find out an unused port.
Considering port 126 is unused & smtp2 is the service, you can make following changes in the file.
smtp2 126/udp mail
smtp2 126/tcp mail
Save the file.
3) Now copy the file /etc/xinetd.d/smtp_psa to /etc/xinetd.d/smtp2_psa.
4) Open the new file and do the following changes in the file.
Replace the first line “service smtp” with “service smtp2“. The file will look as follows:
socket_type = stream
protocol = tcp
wait = no
disable = no
user = root
instances = UNLIMITED
env = SMTPAUTH=1 POPLOCK_TIME=20
server = /var/qmail/bin/tcp-env
server_args = -Rt0 /var/qmail/bin/relaylock /var/qmail/bin/qmail-smtpd /var/qmail/bin/smtp_auth /var/qmail/bin/true /var/qmail/bin/cmd5checkpw /var/qmail/bin/true
5) Now restart xinetd service.
6) In order to check if the new port is listening you can issue the following command.
[root@server~]# netstat -tlpn|grep :126tcp 0 0 0.0.0.0:126 0.0.0.0:* LISTEN 1245/xinetd
7) Also you can check functionality of port 126 by issuing following command.
# telnet XX.X.XX.XX 126