From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hannes Frederic Sowa Subject: Re: [PATCH net] tcp: don't allow syn packets without timestamps to pass tcp_tw_recycle logic Date: Tue, 12 Aug 2014 10:08:42 +0200 Message-ID: <1407830922.3313272.151751729.150ABE1E@webmail.messagingengine.com> References: <69ff43477a795a1117302b11583bc8ea8c5dc811.1407802666.git.hannes@stressinduktion.org> <20140811.200807.1174604291924802129.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, fw@strlen.de To: David Miller Return-path: Received: from out3-smtp.messagingengine.com ([66.111.4.27]:40142 "EHLO out3-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752162AbaHLIIn (ORCPT ); Tue, 12 Aug 2014 04:08:43 -0400 Received: from compute5.internal (compute5.nyi.internal [10.202.2.45]) by gateway1.nyi.internal (Postfix) with ESMTP id F131F22B2B for ; Tue, 12 Aug 2014 04:08:42 -0400 (EDT) In-Reply-To: <20140811.200807.1174604291924802129.davem@davemloft.net> Sender: netdev-owner@vger.kernel.org List-ID: On Tue, Aug 12, 2014, at 05:08, David Miller wrote: > From: Hannes Frederic Sowa > 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