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Date:      Tue, 30 Nov 2004 13:29:54 -0500
From:      csnyder <chsnyder@gmail.com>
To:        freebsd-questions@freebsd.org
Subject:   limiting ssh login attempts by ip
Message-ID:  <b7625269041130102969314136@mail.gmail.com>

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I've noticed a marked increase in dictionary attacks against sshd
lately -- tens or even hundreds of connection attempts from the same
IP address within a short timespan.

I wrote a script that creates firewall rules to drop packets from IPs
with more than n login failures over the last 10 minutes, but it's a
half-measure -- in the minute it takes for cron to get to it, an
attacking script can try a lot of different passwords, even with
MaxStartups set low.

How do you protect your servers from this kind of attack? Especially
on where you can't enforce a strict password policy or make everyone
use keys?



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