From owner-freebsd-net@FreeBSD.ORG Fri Aug 1 11:50:16 2008 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 44F55106569C for ; Fri, 1 Aug 2008 11:50:16 +0000 (UTC) (envelope-from ticso@cicely7.cicely.de) Received: from raven.bwct.de (raven.bwct.de [85.159.14.73]) by mx1.freebsd.org (Postfix) with ESMTP id A569F8FC12 for ; Fri, 1 Aug 2008 11:50:15 +0000 (UTC) (envelope-from ticso@cicely7.cicely.de) Received: from cicely5.cicely.de ([10.1.1.7]) by raven.bwct.de (8.13.4/8.13.4) with ESMTP id m71BoC0i044816 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Fri, 1 Aug 2008 13:50:13 +0200 (CEST) (envelope-from ticso@cicely7.cicely.de) Received: from cicely7.cicely.de (cicely7.cicely.de [10.1.1.9]) by cicely5.cicely.de (8.14.2/8.14.2) with ESMTP id m71Bo8nN002777 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Fri, 1 Aug 2008 13:50:09 +0200 (CEST) (envelope-from ticso@cicely7.cicely.de) Received: from cicely7.cicely.de (localhost [127.0.0.1]) by cicely7.cicely.de (8.14.2/8.14.2) with ESMTP id m71Bo8wt076589; Fri, 1 Aug 2008 13:50:08 +0200 (CEST) (envelope-from ticso@cicely7.cicely.de) Received: (from ticso@localhost) by cicely7.cicely.de (8.14.2/8.14.2/Submit) id m71Bo7B0076588; Fri, 1 Aug 2008 13:50:07 +0200 (CEST) (envelope-from ticso) Date: Fri, 1 Aug 2008 13:50:07 +0200 From: Bernd Walter To: Mike Silbersack Message-ID: <20080801115007.GA76575@cicely7.cicely.de> References: <20080718135931.GA48087@cicely7.cicely.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Operating-System: FreeBSD cicely7.cicely.de 7.0-STABLE i386 User-Agent: Mutt/1.5.11 X-Spam-Status: No, score=-4.3 required=5.0 tests=ALL_TRUSTED=-1.8, AWL=0.120, BAYES_00=-2.599 autolearn=ham version=3.2.5 X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on spamd.cicely.de Cc: freebsd-net@freebsd.org, ticso@cicely.de Subject: Re: TCP zombie connections with 7-RELEASE and STABLE from 15th june X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: ticso@cicely.de List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 01 Aug 2008 11:50:16 -0000 On Fri, Aug 01, 2008 at 12:08:38AM -0500, Mike Silbersack wrote: > > > On Fri, 18 Jul 2008, Bernd Walter wrote: > > >443 is a self written server, but it also happens with port 80 and > >sslproxy. > >The client is a telnet, which disconnects directly after connecting, > >so the disconnect is initiated from the client, which seems to be > >important for this problem to trigger. > > > >You can see that the FIN handshake completes and netstat on the > >client box shows the connection in TIME_WAIT. > >The server however has the connection still in ESTABLISHED state. > > Well, syncookies allow the ack of the 3WHS to establish a connection. > Just a quick look at your tcpdump shows that since you aren't sending any > data you are not advancing the sequence number. As a result, it looks > like one of the ACKs the client sends during connection shutdown may > actually be causing the server to re-establish the connection. Ah - that makes sense. > You might want to file a PR with exact instructions (and code) that'll > easily reproduce this so that it can be solved at some point in the > future. I don't have time to look into it now, although I'd be happy to > code review a fix! Thank you - I will file a PR. -- B.Walter http://www.bwct.de Modbus/TCP Ethernet I/O Baugruppen, ARM basierte FreeBSD Rechner uvm.