We have an issue at one of our sites (site1) where the sites public IP address has been listed on several blacklists - the reason stated is that it does not have a reverse dns record setup.
However, we are not actually running exchange at this site - we are running exchange at another site (site2) and site1 connects to the exchange server at site2 via pop.
I would have thought that emails would be routed (via pop/smtp) through the exchange server at site2 and on delivery would be marked with site2's public IP (Which DOES have RDNS configured correctly).
But according to mxtoolbox.com and the details of each spam server that has listed site1's IP address, we also need a RDNS record for the IP at site1.
Is this correct, and what RDNS do we need (baring in mind there is no Email server at site1)?