I have a client that is not receiving emails from some of the bigger providers like yahoo and hotmail because their IP address is being perceived as a problem. The problem stems from the fact that when you do an NSLOOKUP on their Exchange server's IP address, it doesn't point back to their mailserver.
If you NSLOOKUP mail.domainname.com it resolves correctly to their IP address, say 184.108.40.206 as an example.
However, if you NSLOOKUP 220.127.116.11 it does NOT resolve back to mail.domainname.com. It goes to adsl-99-70-47-155.dsl.ipltin.sbcglobal.net.
The emails is obviously hosted internally on an Exchange Server 2003. The ISP is AT&T who claims that they can't help because we don't use their email services. Network Solutions claims they don't provide Reverse DNS help, either.
To whom should I be asking for a solution? AT&T, Network Solutions, or is this something I should configure on my own Exchagne server? Until I can get 18.104.22.168 to point back to mail.domainname.com, bigger email tubes are going to continue to bounce emails that try to reach my exchange server.