I see there's a RDNS_NONE rule for when the sending IP address has no DNS PTR (reverse DNS) record. But no rule for when that PTR record doesn't have a matching A (forward DNS) record that matches the sending IP?
For example, if you get an email from me, and look up the IP: 64.71.152.40 -> chaosreigns.com Then you can look up that host name and get: chaosreigns.com -> 64.71.152.40 And if that IP didn't match the sending IP, it would fail this test. Is this something that would be accepted into spamassassin if I created a module? Or a feature that would be added if I didn't do it? I block all email that doesn't pass this test at my MTA (postfix reject_unknown_client_hostname), but I understand some people don't. -- "It's a dangerous business, Frodo, going out your front door. You step into the Road, and if you don't keep your feet, there is no knowing where you might be swept off to." - Bilbo Baggins http://www.ChaosReigns.com
