Re: spambots and dictionary attacks

> 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