Perhaps this is too much to ask of SpamAssassin, but...
My server receives a piece of spam that's undeliverable. It looks up the MX for the sender's address, and finds that the IP is 127.0.0.1. It then complains that there's a configuration problem because it's not set up to handle mail for that domain. What I'd like to do is build a SpamAssassin rule that would assign points against messages sent from senders with those 127.0.0.1 MXes. Granted, it won't do any good in these undeliverable/bounce scenarios, but I'm sure there's spams getting through to legit addresses from them as well, and those are what I'd like to put a stop to. Is that possible (without writing a plugin to do it myself)?
