Setting Alternate SMTP port in Plesk on Linux

Getting Plesk to listen for SMTP connections on an alternate port is not that difficult to do. However unlike a cPanel environment, configuring Plesk to do so must be done outside of the control panel via the command line.

The procedure outlined below is complex and requires some basic command line knowledge.  Liquid Web’s systems administrators are always available to assist with this or any other issue.  Feel free to contact Liquid Web via Toll Free 1.800.580.4985, International 517.322.0434, or

First a new entry will need to be created in xinetd for the alternate port:

cd /etc/xinetd.d
cp smtp_psa smtp_psa_p26

Next the entry that was just created needs to be modified:

vi smtp_psa_p26

Make the first line say “service smtp_p26” and save the file.

Next edit the services for the system to include the newly created one:

vi /etc/services
smtp_p26 26/tcp mail
smtp_p26 26/udp mail

After editing this, just restart xinetd and the server should be listening on port 26.   A quick way to verify the changes took effect can be done using this command:

netstat -lpn|grep 26

NOTE: Don’t forget to make sure port 26 is open in the firewall.  A walk through on how to do this can be found here:


Liquid Web’s Heroic Support is always available to assist customers with this or any other issue. If you need our assistance please contact us:
Toll Free 1.800.580.4985
International 517.322.0434

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