Rich Kulawiec (rsk) writes:
Best practice is refuse all mail that comes from any host lacking rDNS, since that host doesn't meet the minimum requirements for a mail server.
No, that's utterly stupid. You're excluding countries which have poor infrastructure or clueless ISPs (usually legacy telco operators) who can't be bothered to administrate IN-ADDR.ARPA delegations for their customers. It doesn't help, and only encourages people in these countries to go for @{hotmail|yahoo|gmail}. Millions of botnet PCs have valid reverses.
Yes, some of these also impact non-spamming but broken mail servers, however, this is usually the only way to get the attention of their operators and persuade them to effect repairs.
You're kidding, right ? They don't give a rat's ass.
Locally, .name, .info and .tv are permanently blacklisted, and I recommend this to others: they're all heavily spammer-infested. .biz is not blacklisted at the moment, largely because it's been so badly ravaged that spammers *appear* to be abandoning it.
"Bomb the bridge, salt the earth" approach ?