James Reynolds: > I use check_sender_access and DISCARD to throw away about 1500-4000 > messages a day from .top domains (which is about the volume of my > legit email). I looked into it and most of them are registered > to namecheap.com, which appears to sell the names for for $.98 > each. I did a little research into Namecheap's reputation and I > found one thread calling them friendly to spammers.
If you have reasons to believe that a certain DNS server is hosting spammer domains, you can use check_client_ns_access, check_helo_ns_access and check_sender_ns_access to block present future spam. It helped me to block a persistent spammer who was constantly changing domain names, but who kept using the same DNS server. Wietse