every ip can have only one reverse dns name, but many domains could point to one ip.
i dont know exactly if this solves your problem, but for a right configured mailserver, its better to use reversedns name = fqdn of your box and you have to have a dns.zone like this for example:
@ IN MX 10 yourserver
smtp IN CNAME yourserver
yourserver IN A ip.from.yourserver
with smtp.example.com you can reach imap and smtp server to send/recieve mails with your client
Last edited by Cirox; 19th March 2006 at 02:09.