From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264377AbUGFTko (ORCPT ); Tue, 6 Jul 2004 15:40:44 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264367AbUGFTko (ORCPT ); Tue, 6 Jul 2004 15:40:44 -0400 Received: from mail.shareable.org ([81.29.64.88]:25520 "EHLO mail.shareable.org") by vger.kernel.org with ESMTP id S264358AbUGFTkm (ORCPT ); Tue, 6 Jul 2004 15:40:42 -0400 Date: Tue, 6 Jul 2004 20:40:34 +0100 From: Jamie Lokier To: Stephen Hemminger Cc: netdev@oss.sgi.com, linux-net@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] fix tcp_default_win_scale. Message-ID: <20040706194034.GA11021@mail.shareable.org> References: <32886.63.170.215.71.1088564087.squirrel@www.osdl.org> <20040629222751.392f0a82.davem@redhat.com> <20040630152750.2d01ca51@dell_ss3.pdx.osdl.net> <20040630153049.3ca25b76.davem@redhat.com> <20040701133738.301b9e46@dell_ss3.pdx.osdl.net> <20040701140406.62dfbc2a.davem@redhat.com> <20040702013225.GA24707@conectiva.com.br> <20040706093503.GA8147@outpost.ds9a.nl> <20040706114741.1bf98bbe@dell_ss3.pdx.osdl.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20040706114741.1bf98bbe@dell_ss3.pdx.osdl.net> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Stephen Hemminger wrote: > Recent TCP changes exposed the problem that there ar lots of really > broken firewalls that strip or alter TCP options. When the options > are modified TCP gets busted now. The problem is that when we > propose window scaling, we expect that the other side receives the > same initial SYN request that we sent. If there is corrupting > firewalls that strip it then the window we send is not correctly > scaled; so the other side thinks there is not enough space to send. If a firewall strips the window scaling option in both directions, then window scaling is disabled (RFC 1323 section 2.2). Are you saying there are broken firewalls which strip TCP options in one direction only? -- Jamie