netdev - Re: [PATCH net] tcp: don't allow syn packets without timestamps to pass tcp_tw

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Message-Id: <1407830922.3313272.151751729.150ABE1E@webmail.messagingengine.com>
Date:	Tue, 12 Aug 2014 10:08:42 +0200
From:	Hannes Frederic Sowa <hannes@...essinduktion.org>
To:	David Miller <davem@...emloft.net>
Cc:	netdev@...r.kernel.org, fw@...len.de
Subject: Re: [PATCH net] tcp: don't allow syn packets without timestamps to pass
 tcp_tw_recycle logic



On Tue, Aug 12, 2014, at 05:08, David Miller wrote:
> From: Hannes Frederic Sowa <hannes@...essinduktion.org>
> Date: Tue, 12 Aug 2014 02:21:36 +0200
> 
> > Thus this broken situation could easily arise by a Linux and Windows
> > box sharing one IP address and talking to a tcp_tw_recycle enabled
> > server.
> 
> As Eric Dumazet mentioned, timewait recycling does not work if any
> traffic goes through a NAT box.
> 
> So this situation of two boxes "sharing one IP address" fundamentally
> makes timewait recycling unusable.

Exactly, I'll just throw away the SYN packet instead of opening a
connection where we couldn't very if the preconditions for timewait
recycling did not hold.

Bye,
Hannes
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