Possible Duplicate:
How does a Reverse DNS lookup work with regards to spam filters?
I have a question about setting a reverse DNS record for my mail server.
Which is the best way to configure:
1.) The IP address reverses to the domain that is sending the email (ie. @mydomain.com)
2.) The MX record target for all domains on the mail server (ie mail.mailserver.com)
Any help is appreciated.