I have a server hosting with one domain and several subdomain a records with dedicated by different IPs.
In order to avoid any possibility of blacklisting of one IP, I would like to make sure that each subdomain uses its own IP to send mail and that the server primary IP or host name info does not appear in the message received header.
I am not sure of what are the EXIM configurations which need to be made to achieve that. Can somebody provide me the full description of what needs to be done or direct me to a link providing that?
Yes. You will have to update your new mail IP in /etc/mailips file and enable following 2 options in WHM's Exim Configuration Manager to change mail server IP of cpanel server
Reference /etc/mailhelo for outgoing SMTP HELO
Reference /etc/mailips for outgoing SMTP connections