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Date:      Thu, 4 Nov 2004 13:53:01 -0500
From:      Charles Swiger <cswiger@mac.com>
To:        Nathan Kinkade <nkinkade@ub.edu.bz>
Cc:        freebsd-questions@freebsd.org
Subject:   Re: kernel: Limiting open port RST
Message-ID:  <C0C39C5D-2E92-11D9-8097-003065ABFD92@mac.com>
In-Reply-To: <20041104181808.GR13601@gentoo-npk.bmp.ub>
References:  <20041104181808.GR13601@gentoo-npk.bmp.ub>

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On Nov 4, 2004, at 1:18 PM, Nathan Kinkade wrote:
> I am getting a tremendous amount of messages on a particular server
> saying something close to:
>
> kernel: Limiting open port RST response from 302 to 200 packets/sec

This generally means the system is being portscanned.

> I understand the reasons for the message, but I'm having a hard time
> tracking down a possible point source.  Neither ethereal nor tcpdump
> seem to be picking up any packets with the TCP RST bit set.  I have
> tried this, for example:
[ ... ]
> TCP and UDP blackhole sysctls are also already
> setup, and it appears that the RST packets are being sent out to
> internet hosts with a dstport of 80.  The machine being affected is
> running squid.

If you turn on the blackhole sysctls, then your machine will not 
generate RST packets.  Caveat operator.  :-)

> Does anyone have advice on this?

If this machine is not supposed to be completely exposed on the 'net, 
consider putting it behind a firewall.

-- 
-Chuck



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