From owner-freebsd-net@FreeBSD.ORG Tue Mar 2 21:47:11 2004 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id C2B0D16A4CF for ; Tue, 2 Mar 2004 21:47:11 -0800 (PST) Received: from gw.catspoiler.org (217-ip-163.nccn.net [209.79.217.163]) by mx1.FreeBSD.org (Postfix) with ESMTP id 8CD8943D1F for ; Tue, 2 Mar 2004 21:47:11 -0800 (PST) (envelope-from truckman@FreeBSD.org) Received: from FreeBSD.org (mousie.catspoiler.org [192.168.101.2]) by gw.catspoiler.org (8.12.9p2/8.12.9) with ESMTP id i235l37E000190; Tue, 2 Mar 2004 21:47:07 -0800 (PST) (envelope-from truckman@FreeBSD.org) Message-Id: <200403030547.i235l37E000190@gw.catspoiler.org> Date: Tue, 2 Mar 2004 21:47:03 -0800 (PST) From: Don Lewis To: eugen@kuzbass.ru In-Reply-To: <40456D3C.773A3C29@kuzbass.ru> MIME-Version: 1.0 Content-Type: TEXT/plain; charset=us-ascii cc: net@FreeBSD.org Subject: Re: Frozen connections X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 03 Mar 2004 05:47:11 -0000 On 3 Mar, Eugene Grosbein wrote: > H! > > I'm experiencing strange problems with HTTP connections between > two machines connected using 100Mbit ethernet switch. > Client is Windows 2000 SP4 (named kost), > server is FreeBSD 4.9/Apache 1.3.27 (named www). > --------------------------------------------------------------------------- > Packet 90 > TIME: 12:06:51.278337 (0.279509) > LINK: 00:90:27:AB:08:88 -> 00:90:27:35:05:1B type=IP > IP: www -> kost hlen=20 TOS=00 dgramlen=41 id=64CE > MF/DF=0/1 frag=0 TTL=64 proto=TCP cksum=A7ED > TCP: port http -> 2134 seq=1179931920 ack=1524903532 > hlen=20 (data=1) UAPRSF=010000 wnd=58400 cksum=FC43 urg=0 > DATA: t > --------------------------------------------------------------------------- > Packet 91 > TIME: 12:06:51.278615 (0.000278) > LINK: 00:90:27:35:05:1B -> 00:90:27:AB:08:88 type=IP > IP: kost -> www hlen=20 TOS=00 dgramlen=40 id=10E6 > MF/DF=0/1 frag=0 TTL=128 proto=TCP cksum=BBD6 > TCP: port 2134 -> http seq=1524903532 ack=1179931920 > hlen=20 (data=0) UAPRSF=010000 wnd=0 cksum=5466 urg=0 > DATA: > > As you see, last pair of packets repeats many times > and transfer is stalled here. What's wrong and who is guilty? It looks like the client is the guilty party. The server is sending 1-byte long window probes, and the client is responding with an ACK packet that is advertising a receive window of 0. I'd be suspicious of the application software on the client. Can you try a different web browser, or even fetch the same URL using something like telnet?