On Tue, 10 Sep 2002 09:12:15 PDT, Joe St Sauver said:
Actually, our experience *does* follow the backoff paradigm: if you block a particular source of spam, that rejection *does* seem to trigger "message volume" backoff at the source, with only periodic check probes apparently designed to see if the spam source is really still blocked (and of course it really still is).
Yes - but since they need to have N replies to their spam to make it worth the effort, they will just pound on somebody ELSE. I saw one quote from a very unapologetic spammer who was complaining that with all these blocks he had to send a lot more spam and his costs were up 1000% as a result. Let's say a spammer needs 100 replies to turn a profit, and 1% of the things that make it into a mailbox get a reply. If nobody blocks spam, then the spammer only needs to send 10K messages before he profits. If 99% of spam is blocked, he has to send a million. That's why we're seeing statistics like "receives 2 billion pieces of mail a day and 80% is spam". Think of it like a host with multiple A records - if one A goes down, they *do* stop trying that one, but they then fail to use backoff on the OTHER addresses.... ;) -- Valdis Kletnieks Computer Systems Senior Engineer Virginia Tech