From owner-freebsd-net@FreeBSD.ORG Fri Jul 31 21:41:45 2009 Return-Path: Delivered-To: net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id B3333106566B for ; Fri, 31 Jul 2009 21:41:45 +0000 (UTC) (envelope-from Michael.Tuexen@lurchi.franken.de) Received: from mail-n.franken.de (drew.ipv6.franken.de [IPv6:2001:638:a02:a001:20e:cff:fe4a:feaa]) by mx1.freebsd.org (Postfix) with ESMTP id 4E19A8FC12 for ; Fri, 31 Jul 2009 21:41:45 +0000 (UTC) (envelope-from Michael.Tuexen@lurchi.franken.de) Received: from [192.168.1.100] (p508FE6D1.dip.t-dialin.net [80.143.230.209]) by mail-n.franken.de (Postfix) with ESMTP id 950101C0B4607; Fri, 31 Jul 2009 23:41:43 +0200 (CEST) Message-Id: From: =?ISO-8859-1?Q?Michael_T=FCxen?= To: In-Reply-To: Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Content-Transfer-Encoding: 7bit Mime-Version: 1.0 (Apple Message framework v935.3) Date: Fri, 31 Jul 2009 23:41:42 +0200 References: X-Mailer: Apple Mail (2.935.3) Cc: net@freebsd.org Subject: Re: TCP RST question X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 31 Jul 2009 21:41:45 -0000 On Jul 31, 2009, at 3:57 PM, wrote: > Hi all, > > I'm looking at our TCP stack and found a change that was introduced > with > the syncache. The original BSD code did send an RST segment when the > connection timed out in SYN-RECEIVED. The TCP would retransmit the > SYN+ACK several times and then give up and RST the peer. > > With syncache, however, our TCP doesn't send the RST anymore. It just > silently discards local state. > > So the question is whether TCP is supposed to RST or not. Looking at > RFC793 I found nothing useful. It talks about sending RSTs as response > to incoming segments and it looks like TCP is never supposed to give > up > retransmitting. The state diagram has no line from SYN-RECEIVED to > CLOSED. Stevens, on the other hand, has this line and it is labeled > 'send: RST'. > > So the questions are: > > - is TCP supposed to send an RST when it times out in SYN-RECEIVED? > - why was this changed (I suppose it is just one of the regressions > introduced with the syn-cache). > > harti > > NB: does anybody know a good mailing list where this kind of questions > can be discussed? tsvwg@ietf.org tcpm@ietf.org Best reagrds Michael > _______________________________________________ > freebsd-net@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-net > To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org" >