In order to change the exim interface IP, do the following :

-SSH to your server and edit the file – /etc/mailips : This file controls the IP address from which each domains are allowed to send the mails. If the file is not present, create it. Open the file for editing using your preferred text editor. You will need to configure this file in the following way:

*: (<- desired IP )

^ the option * denotes the entire list of domains in the server. If you require just one domain to send from a different IP, specify the domain there instead of ‘*’

– Disable the following from WHM

From WHM »Service Configuration »Exim Configuration Manager>> Domain and IPs>> Send mail from account’s dedicated IP address "on"

– Enable this option,

Reference /etc/mailips for outgoing SMTP connections.

And now, restart the exim service.