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Network Security Focus-Linux
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Re: spambots and dictionary attacks

Subject: Re: spambots and dictionary attacks
Date: Wed, 22 Nov 2006 10:30:46 -0700
Greylisting is a two-edged sword, though, that may not only cause
noticable delays in mail delivery, but also legit mails to be rejected.

Only for the first email if the greylisting system has any sense (i.e. OpenBSD's spamd), plus most allow whitelisting.


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.

Sure and then the hosts are behaving like real email servers which is vastly more expensive (computationally/etc.) than just blasting stuff out. If my OpenBSD spamd delays delivery for 4 hours that gives my other defenses 4 hours to react (i.e. for blacklists to be updated, whatever). We're never going to have 100% effective anti spam solutions, but that's no reason to give up. I'd rather get 2-3 spams a day than 1000.


Regards
Ansgar Wiechers

-Kurt


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