From: Pablo Neira Ayuso <pablo@netfilter.org>
To: Jan Engelhardt <jengelh@computergmbh.de>
Cc: Netfilter Developer Mailing List <netfilter-devel@vger.kernel.org>
Subject: Re: UDP entries do not list ctstate
Date: Tue, 19 Feb 2008 01:39:56 +0100 [thread overview]
Message-ID: <47BA255C.1080801@netfilter.org> (raw)
In-Reply-To: <Pine.LNX.4.64.0802190111280.26274@fbirervta.pbzchgretzou.qr>
Hi Jan,
Jan Engelhardt wrote:
> to figure out what Netfilter actually does, we add a rule to match
> incoming DNS replies for demonstrational purposes:
>
> iptables -I INPUT -p udp --sport 53 -m conntrack --ctstate
> ESTABLISHED
>
> as one would expect, ESTABLISHED matches. Now, after the DNS reply has
> been received, running `conntrack -L | grep udp` does not show the
> string "ESTABLISHED" at all, even if I run it within the UDP conntrack
> timeout. Glitch/Bug in /usr/sbin/conntrack?
The output is compatible with /proc/net/ip_conntrack which doesn't show
the generic states for UDP. Instead, it shows the flag assured when we
have seen traffic in both directions.
BTW, you can also `use conntrack -L -p udp' to filter so you don't need
to use grep for this particular case.
--
"Los honestos son inadaptados sociales" -- Les Luthiers
prev parent reply other threads:[~2008-02-19 0:40 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-02-19 0:13 UDP entries do not list ctstate Jan Engelhardt
2008-02-19 0:39 ` Pablo Neira Ayuso [this message]
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