Received: with ECARTIS (v1.0.0; list netdev); Tue, 06 Jul 2004 12:40:43 -0700 (PDT) Received: from mail.shareable.org (mail.shareable.org [81.29.64.88]) by oss.sgi.com (8.12.10/8.12.9) with SMTP id i66Jeegi007443 for ; Tue, 6 Jul 2004 12:40:41 -0700 Received: from mail.shareable.org (localhost [127.0.0.1]) by mail.shareable.org (8.12.8/8.12.8) with ESMTP id i66JeZ81011093; Tue, 6 Jul 2004 20:40:35 +0100 Received: (from jamie@localhost) by mail.shareable.org (8.12.8/8.12.8/Submit) id i66JeY4T011091; Tue, 6 Jul 2004 20:40:34 +0100 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 X-archive-position: 6677 X-ecartis-version: Ecartis v1.0.0 Sender: netdev-bounce@oss.sgi.com Errors-to: netdev-bounce@oss.sgi.com X-original-sender: jamie@shareable.org Precedence: bulk X-list: netdev Content-Length: 725 Lines: 16 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