From: Pablo Neira Ayuso <pablo@netfilter.org>
To: Florian Westphal <fw@strlen.de>
Cc: netfilter-devel@vger.kernel.org
Subject: Re: [PATCH next] netfilter: conntrack: avoid large timeout for mid-stream pickup
Date: Thu, 20 Jun 2013 11:45:42 +0200 [thread overview]
Message-ID: <20130620094542.GA11331@localhost> (raw)
In-Reply-To: <1371137488-16428-1-git-send-email-fw@strlen.de>
On Thu, Jun 13, 2013 at 05:31:28PM +0200, Florian Westphal wrote:
> When loose tracking is enabled (default), non-syn packets cause
> creation of new conntracks in established state with default timeout for
> established state (5 days). This causes the table to fill up with UNREPLIED
> when the 'new ack' packet happened to be the last-ack of a previous,
> already timed-out connection.
>
> Consider:
>
> A 192.168.x.52792 > 10.184.y.80: F, 426:426(0) ack 9237 win 255
> B 10.184.y.80 > 192.168.x.52792: ., ack 427 win 123
> <61 second pause>
> C 10.184.y.80 > 192.168.x.52792: F, 9237:9237(0) ack 427 win 123
> D 192.168.x.52792 > 10.184.y.80: ., ack 9238 win 255
>
> B moves conntrack to CLOSE_WAIT and will kill it after 60 second timeout,
> C is ignored (FIN set), but last packet (D) causes new ct with 5-days timeout.
>
> Use UNACK timeout (5 minutes) instead to get rid of these entries sooner
> when in ESTABLISHED state without having seen traffic in both directions.
Applied, thanks!
prev parent reply other threads:[~2013-06-20 9:45 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-13 15:31 [PATCH next] netfilter: conntrack: avoid large timeout for mid-stream pickup Florian Westphal
2013-06-13 17:21 ` Jozsef Kadlecsik
2013-06-20 9:45 ` Pablo Neira Ayuso [this message]
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