This is going to be a short guide, but it will be helpful for people who are reselling their server. What this does is it enables the resold (sub cpanel) accounts that are on a different IP address than the server’s main IP so they will send from their IP address and not your server’s main, which is the default setting.
The reason why you will want to do this is, because if you have a resold that got hacked and are now spamming the world from your server they will then get blacklisted by all of the RBLs out there.
If you have it set up to send from the server’s main IP address then everyone on the server is now blacklisted; but if they are sending from their own IP address then they are only affecting themselves. Giving you only one unhappy customer not hundreds.
You will need to be able to log into the WHM, if you need a refresher Click Here.
To change the outbound sending IP for Exim you will need to search for Exim Configuration Manager, in the top left search box in WHM, and select Exim Configuration Manager.
Once there you will need to click on the Domains and IPs button on the second navigation bar.
Click the On button for: Send mail from account’s dedicated IP address. Then the other options will go grey and then click save. You are now all done.