How to force Exim to listen on certain IPs (WHM)
We have recently had the need for Exim SMTP server to only listen on a select IP. The server in question had about 7IPs - only one of them needed to act as a SMTP server. After a bit of research, this is possible via the WHM interface.
First, navigate to the Exim Configuration Manger in WHM and select the Advanced Editor tab. You'll need to scroll down to the "Add additional configuration setting" button
You need to add
local_interfaces in the first field and
127.0.0.1 : YOUR.IP.GOES.HERE
in the second, this'll only work for IPv4.
Finally, scroll all the way to the bottom and click Save - once Exim restarts you should be good to go!