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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: How do you stop outgoing spam?
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 Attachment:
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