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Re: Botnet detection (pre-greet experiments)

From: Wietse Venema (wietseporcupine.org)
Date: Wed Mar 04 2009 - 11:33:44 CST


Jacqui Caren:
> Wietse Venema wrote:
> > Although the idea of proactive botnet detection has merit, building
> > delays into the SMTPD process is very problematic. It causes Postfix
> > to waste more time on bogus SMTP clients, so that it reaches the
> > "all SMTP servers busy" condition sooner.
>
> I thought some smtp reverse proxy front ends already did this.
> The catch "talk ahead" bots by listening for talk for a short period and

Yes, they do, including spamd that I reference several times
in the text that you deleted.

        Wietse