Received: with ECARTIS (v1.0.0; list netdev); Wed, 07 Jul 2004 18:45:30 -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 i681jRgi025214 for ; Wed, 7 Jul 2004 18:45:28 -0700 Received: from mail.shareable.org (localhost [127.0.0.1]) by mail.shareable.org (8.12.8/8.12.8) with ESMTP id i681ih81020868; Thu, 8 Jul 2004 02:44:43 +0100 Received: (from jamie@localhost) by mail.shareable.org (8.12.8/8.12.8/Submit) id i681ihO2020866; Thu, 8 Jul 2004 02:44:43 +0100 Date: Thu, 8 Jul 2004 02:44:43 +0100 From: Jamie Lokier To: bert hubert , "David S. Miller" , Stephen Hemminger , netdev@oss.sgi.com, linux-net@vger.kernel.org, linux-kernel@vger.kernel.org, ALESSANDRO.SUARDI@ORACLE.COM Subject: Re: preliminary conclusions regarding window size issues Message-ID: <20040708014443.GE17266@mail.shareable.org> References: <20040707232757.GA14471@outpost.ds9a.nl> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20040707232757.GA14471@outpost.ds9a.nl> User-Agent: Mutt/1.4.1i X-archive-position: 6791 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: 722 Lines: 19 bert hubert wrote: > Alessandro never sees these packets! ... > My current feeling is that some kind of QoS device is interfering, > and that the 'wscale gets stuffed' theory is wrong in this case. > > I recall that 'Packeteer' QoS devices try to mess with windows. It's a bit fiddly to arrange, but can you repeat the test and artificially lower the TTL for these packets which disappear? An iptable mangle rule would do the trick -- mangle the TTL only on packets which match this point in the trace. The idea is to reduce the TTL like traceroute does, so you can see which hop is causing these packets to disappear -- perhaps it'll stand out proudly as a QoS device which can be named, blamed and shamed. -- Jamie