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From: Jason Opperisano <opie@817west.com>
To: netfilter@lists.netfilter.org
Subject: Re: ipt_TCMSS.c -- A slight problem i'm having
Date: Mon, 1 Nov 2004 14:02:59 -0500	[thread overview]
Message-ID: <20041101190259.GA18883@bender.817west.com> (raw)
In-Reply-To: <424BCB4EA242A1429A8AF0548E8CFF0E123959@apexexchange.ApexSoftware.Com>

On Mon, Nov 01, 2004 at 11:50:37AM -0500, Scott Knake wrote:
<snip>
> That is a little excerpt from ipt_TCMSS.c. The problem is that somebody
> DoS'd me with syn Packets that contained data len(header) <!=
> len(packet). I have a little ServGate SG100 router that handles my T1
> connection. The router physically seized for the 5 minutes or so while
> he packeted because of the amount of logging I'm guessing. How can I
> block this with just an iptables ruleset? I'm trying not to limit the
> incoming number of syn packets and I cant recompile netfilter since it
> is running on a flavored kernel custom for the router. How am I going to
> prevent this in the future?

  iptables -t mangle -I PREROUTING -i $external_if -p tcp --syn \
    -m length ! --length 60 -j DROP

-j

--
"I bet Einstein turned himself all sorts of colors before he invented
the light bulb."
        --The Simpsons


      reply	other threads:[~2004-11-01 19:02 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-11-01 16:50 ipt_TCMSS.c -- A slight problem i'm having Scott Knake
2004-11-01 19:02 ` Jason Opperisano [this message]

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