ServerBuddies Support Blog

Get exim to listen on another port other than 25

Some ISP’s are now blocking outgoing port 25 which prevents user from using smtp via their server. The workaround is to get exim to listen on another port other than 25 to bypass the ISP’s block.

For example, to get exim to listen on both port 25 and port 587, you’d add the following code to the very top of the /etc/exim.conf file:

Once saved, restart exim:
Redhat:
/sbin/service exim restart

FreeBSD:
/usr/local/etc/rc.d/exim restart

More: http://www.exim.org/exim-html-4.40/doc/html/spec_13.html#SECT13.5

Configure exim to listen on additional ports

Exim is a popular Message Transfer Agent (MTA) used on Unix systems. By default Exim will be listening on port 25. To make Exim listening on other additional port, say 26, add the following line to /etc/exim.conf.

After this restart Exim using the following commands.

This will make Exim to listen on ports 25 as well as 26. Make sure you open the port 26 in the server firewall.