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How to change the default SMTP port for Postfix

This document (7000872) is provided subject to the disclaimer at the end of this document.


SuSE Linux Enterprise Server 10


How to change the default SMTP port (25) for Postfix


Launch a terminal, become the root user and edit the file located in /etc/postfix directory:
su - 
vi /etc/postfix/

Look for the line: 
smtp            inet      n      -       n       -       -        smtpd

replace "smtp" with the port number that postfix should listen on, save the file and restart the postfix.
/etc/init.d/postfix restart

Additional Information

Notes: On the linux server, by default, postfix is running and listens on SMTP port 25. Postfix is used to send server related messages to the root user. If GroupWise Internet Agent (GWIA) need to be installed on the same linux server, you must change the listen port for one of the SMTP daemons (Postfix or GWIA) to something other than the default (port 25) so that both can co-exist on the same server.


This Support Knowledgebase provides a valuable tool for SUSE customers and parties interested in our products and solutions to acquire information, ideas and learn from one another. Materials are provided for informational, personal or non-commercial use within your organization and are presented "AS IS" WITHOUT WARRANTY OF ANY KIND.

  • Document ID:7000872
  • Creation Date: 03-Mar-2009
  • Modified Date:12-Aug-2022
    • SUSE Linux Enterprise Server

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