From owner-freebsd-net@FreeBSD.ORG Tue Apr 3 22:28:41 2012 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 C260D106564A for ; Tue, 3 Apr 2012 22:28:41 +0000 (UTC) (envelope-from darrenr@freebsd.org) Received: from out1-smtp.messagingengine.com (out1-smtp.messagingengine.com [66.111.4.25]) by mx1.freebsd.org (Postfix) with ESMTP id 8A3C88FC17 for ; Tue, 3 Apr 2012 22:28:41 +0000 (UTC) Received: from compute6.internal (compute6.nyi.mail.srv.osa [10.202.2.46]) by gateway1.nyi.mail.srv.osa (Postfix) with ESMTP id D05CB2130A for ; Tue, 3 Apr 2012 18:28:34 -0400 (EDT) Received: from frontend2.nyi.mail.srv.osa ([10.202.2.161]) by compute6.internal (MEProxy); Tue, 03 Apr 2012 18:28:34 -0400 DKIM-Signature: v=1; a=rsa-sha1; c=relaxed/relaxed; d= messagingengine.com; h=message-id:date:from:reply-to :mime-version:to:cc:subject:references:in-reply-to:content-type :content-transfer-encoding; s=smtpout; bh=YwarzRfKkX5FWJaXNeYb6Y ajuNc=; b=CusjTXeEt302Kk1k28QvGEN4dlI85HJwwqxtjzbBo00HZkl4OCeyHd euq6UVDLDosgwlEl0u8BCjgitP9DNSxEYugro87F13wj4tCeKpelS+Yp7HPLGxrk VXPISuxh4HfKArzH8Xfz6aGkquUo6o1fFs4AvwX41U23T13C0ZPwY= X-Sasl-enc: VD4PBt9TE6llituzijb+318JWI7vbgWGTsHbVNPFAo1z 1333492114 Received: from [192.168.1.124] (dsl-202-45-110-141-static.VIC.netspace.net.au [202.45.110.141]) by mail.messagingengine.com (Postfix) with ESMTPSA id D592F4825B3; Tue, 3 Apr 2012 18:28:33 -0400 (EDT) Message-ID: <4F7B798F.3080203@freebsd.org> Date: Wed, 04 Apr 2012 08:28:31 +1000 From: Darren Reed Organization: FreeBSD User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-AU; rv:1.9.2.28) Gecko/20120306 Thunderbird/3.1.20 MIME-Version: 1.0 To: Andre Oppermann References: <4F75C1A3.4030401@freebsd.org> <4F75D9ED.7080707@freebsd.org> <4F780373.6030107@freebsd.org> <4F7AFEEF.60708@freebsd.org> <4F7B1981.1050009@freebsd.org> <4F7B3098.3090901@freebsd.org> In-Reply-To: <4F7B3098.3090901@freebsd.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: freebsd-net@freebsd.org Subject: Re: FreeBSD TCP ignores zero window size X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: darrenr@freebsd.org List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 03 Apr 2012 22:28:41 -0000 On 4/04/2012 3:17 AM, Andre Oppermann wrote: > On 03.04.2012 17:38, Darren Reed wrote: >> On 3/04/2012 11:45 PM, Andre Oppermann wrote: >>> It's the other way around. remote.ssh is sending old data >>> which freebsd82.62922 has already ack'ed. The sessions seems >>> to be de-synchronized, perhaps some middle box mucking with >>> the segments trying to modulate something? >> >> I suspect that the ISP is dropping packets and/or applying >> some other means of throttling the connection. So, yes. > > That doesn't explain it. The other side is retransmitting data > we have already received and acknowledged! There is not > nothing we can do on our side. That behavior is totally > non-compliant. > > The zero-window is not involved in this as it would affect > FreeBSD sending data, not the other end sending data. > > Can you try to find out what kind of middle-box is mucking > TCP here on your side and the other side? It must be some > device that actively touches the TCP session transiting > through it. A router with active queue management (like WFQ > or RED) is not enough to cause this behavior. > > What is the OS of your remote.ssh? I should add that given the other end of this is NetBSD I have also been following up discussion of this behaviour on their appropriate list too. That discussion can be found here: http://mail-index.netbsd.org/tech-net/2012/04/01/msg003203.html The currently last installment of which is here: http://mail-index.netbsd.org/tech-net/2012/04/03/msg003216.html Darren