Log into cPanel/WHM on your dedicated or cloud server:

By default Exim will be using the main server shared IP address to send mails.

1. Open the Exim configuration file

# vi /etc/exim.conf

2. Locate the section of the file that contains the following:

remote_smtp:
driver = smtp

3. Replace this section with the following modified version :

remote_smtp:
driver = smtp
interface = <IP>

4. Restart Exim using the following commands

# service exim restart
or
# /etc/init.d/exim restart

This will change the outgoing mail server IP of the exim mail server.