82% of email is spam

82% of email is spam

Posted May 6, 2004 12:29 UTC (Thu) by pizza (subscriber, #46)
Parent article: 82% of email is spam

Perhaps the most promising solution I've seen is greylisting. The idea is that all "unknown" senders get sent a temporary "retry later" error, and legit MTAs will do just that, but spammers/worms/virii/etc won't bother, and will require a much more sophisticated "zombie" to send mail.

This has cut the spam I receive down to a small trickle from the couple hundred a day, to say nothing for the other users of the system I admin. (The only spam I get now is stuff sent via massive BCCs using a rather traditional e-mail client)

The nice thing about this is that it happens before mail is delivered, so you save on the bandwidth, storage, and cpu costs of post-delivery filtering.

http://projects.puremagic.com/greylisting/

There are multiple implementations of this technique now.

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