Here is the scenario:
mail.domain.com is hosted to IP 220.127.116.11 inbound at serverX(which is a SPAM filter front end), outbound mail comes from serverY(actual mail server) at IP 18.104.22.168 for same domain. Incoming has no issues since MX and RDNS reflect IP 22.214.171.124, but outbound has some issues when the server receiving the e-mail at anothermail.anotherdomain.com checks the IP and sees RDNS at IP 126.96.36.199 coming from server IP 188.8.131.52.
My options include:
1)pointing outbound mail via smart host to 184.108.40.206 and all would be good, but am having issues getting that to work.
2)Changing name of server at 220.127.116.11 to mail2.domain.com and creating another RDNS for it. Not sure if MX is required for outbound or if anything else also needs to be done.