Follow the instructions below to configure an additional SMTP port for your MTA:
QMail (Parallels Plesk Panel 8.x, 9.x)
Choose any unused port and add it to the /etc/services file. For example:
smtp_alt 25025/tcp # new SMTP port
If you have 'xinetd' as a super-server, make a copy of /etc/xinetd.d/smtp_psa to /etc/xinetd.d/smtp_psa_alt and correct the service line within the new file:
Restart xinetd `/etc/init.d/xinetd restart` and the SMTP connections will be accepted on both the standard and 25025 ports. You may also need to reconfigure Horde IMP (webmail) settings so they also use the alternative SMTP port. This can be done in /etc/psa-horde/imp/servers.php file under the smtpport parameter for both IMAP and POP3 servers. If you have a 'netd' super-server (Debian or FreeBSD), modify inetd.conf to enable an additional SMTP port:
grep '^smtp ' /etc/inetd.conf | sed 's/^smtp/smtp_alt/' >> /etc/inetd.conf
and restart inetd.
NOTE: If you wish to disable the default (25) port completely and continue using only an alternate one, please do not block the 25 port at the firewall and do not remove the 'smtp_psa' service from the xinetd/inetd but set the default SMTP service to be listened only on 127.0.0.1 by adding 'bind = 127.0.0.1' to /etc/xinetd.d/smtp_psa. Otherwise, the SMTP service status will be displayed incorrectly in Plesk CP. Plesk determines SMTP service status by checking the 25th port and the port number is hardcoded there.
Postfix (Parallels Plesk Panel 9.x, 10.x, ...)
Add the following line to the Postfix configuration file /etc/postfix/master.cf:
<IP_Address>:<port> inet n - n - - smtpd
where <IP_Address> is the IP address of your server and <port> is the additional port for the SMTP connection.
If Postfix is configured to use Postfix Before-Queue Content Filter extend the line with the proxy filter settings:
<IP_Address>:<port> inet n - - - - smtpd -o smtpd_proxy_filter=127.0.0.1:10025
Reload the mail service with mailmng after the reconfiguration:
# /usr/local/psa/admin/sbin/mailmng --reload-service
Reloading postfix: [ OK ]
(Parallels Plesk Panel 11.x)
By default, Plesk 11 accepts mail submission on TCP port 587