rather than trumping up your argument with etiquette fascism, how about pointing out a relevant RFC that backs up your [baseless] opinion that a mailserver must accept messages from a site without reverse DNS?
ever heard of RFC 2505? apparently not.
I hadn't read RFC2505 <http://zvon.org/tmRFC/RFC2505/Output/index.html> until now, but I took the time to do so.
It has some good advice, but I didn't see any mention of refusing mail from hosts without reverse DNS. It does talk about refusing mail based on the FQDN that reverse DNS resolves to (section 2.5), but I think it's a stretch to extend that to IP addresses that don't have reverse DNS.
I agree with others that the first post should have gone to Inter7 (perhaps [EMAIL PROTECTED]) and not this list.
If someone wants to add spam filters to their personal mail server that deny mail from hosts without reverse DNS, that's fine with me. If they think it's a good idea and tell others about it, I think it's a good idea for others to provide constructive feedback on why they disagree.
If it's true that spammers don't have reverse DNS on their IP addresses, I wouldn't mind seeing the MTA adding a header like "X-Possible-Spam: Host 18.104.22.168 does not have reverse DNS." and even "X-Possible-Spam: Host 22.214.171.124 resolves to spam.com which does not resolve to 126.96.36.199". Then an email client could filter on that header or SpamAssassin could add a few points to the message's spam score.
-- Tom Collins [EMAIL PROTECTED]