Currently I have my mail register with my ISP as mail.companydomain.com and my FQDN is us.mycompanydomain.us. I am getting NDR from certain ISP because they do a reverse lookup. I want to know what I can do if I register my domain as mail.companydomain.com but my FQDN of my mail server is mailserver.mycompanydomain.local. I have already change the name in advance to point to my FQDN (mailserver.mycompanydomain.com) in the Advance Delivery Tab. But now I cannot recieve any emails nor can I send any mails that does a reverse lookup. Do I have my ISP register mailserver.mycompanydomain.com to point it back to my mail server? Or do I have to have my ISP register mailserver.us.companydomain.com? Also by leaving my mailserver.mycompany.com register does it leave it for attacks?
