From: Pascal Hambourg <pascal.mail@plouf.fr.eu.org>
To: netfilter@lists.netfilter.org
Subject: Re: is it possible to block ip packets that contains experimental tcp options ?
Date: Mon, 21 May 2007 20:27:15 +0200 [thread overview]
Message-ID: <4651E483.9000204@plouf.fr.eu.org> (raw)
In-Reply-To: <1179747134.32083.19.camel@bathory.webcat.no>
Hello,
Glenn Terjesen a écrit :
> What i meant with "experimental tcp options" is that my ids (snort)
> keept logging these "experimental tcp options"
>
> #
> code 76
> length 8
> data 01019DEDBEF00005
>
> I know this aint a snort list, but my servers don't serve any services
> that require this kind of traffic.
>
> So i was wondering if iptables has any way of blocking these.
If you have a black list of options you want to drop (or a white list of
allowed options), what about the "--tcp-option" option of the "tcp" match ?
> These to magic lines fixed it all
> iptables -A FORWARD -p tcp --tcp-flags ALL ALL -j DROP
> iptables -A FORWARD -p tcp --tcp-flags ALL NONE -j DROP
I wonder how these rules could drop packets according to TCP options.
TCP flag combinations are not TCP options.
next prev parent reply other threads:[~2007-05-21 18:27 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-05-17 17:18 is it possible to block ip packets that contains experimental tcp options ? Marc Cozzi
2007-05-17 17:25 ` is it possible to block ip packets that contains experimentaltcp " Paul Blondé
2007-05-21 11:32 ` is it possible to block ip packets that contains experimental tcp " Glenn Terjesen
2007-05-21 11:55 ` Glenn Terjesen
2007-05-21 18:27 ` Pascal Hambourg [this message]
2007-05-22 8:58 ` Glenn Terjesen
-- strict thread matches above, loose matches on Subject: below --
2007-05-16 12:18 Marc Cozzi
2007-05-16 18:04 ` Jan Engelhardt
2007-05-16 9:23 Glenn Terjesen
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