The syntax is IP then colon, space, and domain name similar to as shown here: XXX.XXX.XXX.XXX: domain.com
Now logged into WHM browse to WHM Home » Service Configuration » Exim Configuration Manager » Advanced Editor
Use your browser to search for "smtp_banner". Replace the existing entry in this field from:
"${primary_hostname} ESMTP Exim ${version_number} \#${compile_number} ${tod_full} \n We do not authorize the use of this system to transport unsolicited, \n and/or bulk e-mail."
to the following - INCLUDE QUOTES! :
"${smtp_active_hostname} ESMTP Exim ${version_number} \#${compile_number} ${tod_full} \n We do not authorize the use of this system to transport unsolicited, \n and/or bulk e-mail."
Next, scroll down from that option until you see a blue text box that states "Add Additional Configuration Setting" Click on this box two times. In the first newly created drown-down field, select "smtp_active_hostname" and then enter:
${lookup{$interface_address}lsearch{/etc/mail_reverse_dns}{$value}{$primary_hostname}}In the second newly created drown-down field, select "message_id_header_domain" and then enter:
$smtp_active_hostnameFinally, scroll to the very bottom of the advanced editor and click on "Save". This will allow you to save the custom rules that you have created and they should be maintained through updates and other changes.
