Re: [Exim] Basic teergrubing with Exim 4.11

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Author: Kevin P. Fleming
Date:  
To: Tabor J. Wells
CC: Exim-users
Subject: Re: [Exim] Basic teergrubing with Exim 4.11
Tabor J. Wells wrote:

> On Thu, Dec 12, 2002 at 03:14:44PM -0700,
> Kevin P. Fleming is thought to have said:
>
>
> >Anyone have any more suggestions?
>
>
> You could look for attempted dictionary attacks for any host by using
> $rcpt_fail_count and start delaying when it reachs some threshold.
>

True... I've only seen a few (less than six) dictionary attacks so far, but
that's a good idea (and easy enough to implement).

deny   domains = +local_domains
        message = unknown user
        delay = ${if >{$rcpt_fail_count}{1} {${eval:30*$rcpt_fail_count}}{0}}s
        ! verify = recipient


Or something like that... I've yet to try it.