http://ipadmin.junkemailfilter.com/rdns.php
quote, "However what I can't spoof is if you do a lookup on the fake name I return and it either doesn't resolve or resolves to a different IP address then you know it's not genuine." Well, not genuine, or administered by a pompous professional who thinks he's got a special case where forward and reverse should not match, on purpose. In the course of scoring points for mismatches I've got to ask a few of them why they their DNS records are so... interesting. One guy thought all his hosts' PTR records should give the name of the domain's mail server. Joseph Brennan Lead Email Systems Engineer Columbia University Information Technology
