On 2006-11-21 Steven Jones wrote:
> Most attacks these days seem (vastly) distributed, the most effective
> thing I have found is to use grey listing as this stops 99%+ of botnets
> dead, they simply do not re-try the connection later. Personally I have
> found no other technique as effective.

Greylisting is a two-edged sword, though, that may not only cause
noticable delays in mail delivery, but also legit mails to be rejected.
Not to mention that it'll stop working as soon as it's being used widely
enough to make adjusting to it worthwhile to spammers.

Regards
Ansgar Wiechers
--
"All vulnerabilities deserve a public fear period prior to patches
becoming available."
--Jason Coombs on Bugtraq

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