Question : Reverse DNS lookup

Hi,
    We have installed Exchange 2007 on a new server.All works fine except AOL emails.
They are not able to get our emails but i am able to receive them.
I know to fix it we need to have forward lookup zone which we already have on our  ISP  dns.
Now my question is that do we have to configure our internal dns  to do forward lookup?
If so  then how AOL will be able to do a reverse lookup to my intrnal DNS.

scenario
-----------
External ip :169.25.265.25
Exchange 2007:  192.168.0.6
Internal DNS : 192.168.0.4




   

Answer : Reverse DNS lookup

Reverse DNS checks work by simply checking that a PTR record exists for your mailservers IP in GLOBAL DNS.  They don't check what that entry states, just that it exists.  For example, you could host mail for a few domains on the same Exchange server, but you would only need a single reverse DNS entry.

You can test whether your reverse DNS meets AOL's criteria by checking

http://postmaster.aol.com/tools/rdns.html

More sophisticated tools are now being used by some organisations to prevent spam now though.  SPF records are also worth looking into (although this is outside the context of your question....)