Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sun, 31 Dec 2000 10:58:57 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sun, 31 Dec 2000 10:58:47 -0500 Received: from mailframe.cabinet.net ([213.169.1.9]:48140 "HELO mailframe.cabinet.net") by vger.kernel.org with SMTP id ; Sun, 31 Dec 2000 10:58:33 -0500 Date: Sun, 31 Dec 2000 17:28:05 +0200 (EET) From: Jussi Hamalainen To: Subject: Re: path MTU bug still there? In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 31 Dec 2000, Mikael Abrahamsson wrote: > When the linux box does TCP to the outside it'll use the MTU of > the tunnel (default route is the tunnel) and thus works perfectly > (since TCP MSS will be set low enough to fit into the tunnel). In my case I can't access a problematic host even from the router box. > Could it be some kind of incompability at the tunnel level that > make you unable to receive large packets over the tunnel? Could be. The internet connection is a 64k ISDN link. > Have you tcpdump:ed to see if the tunnel packets actually make it > the way they should? I can't snoop the actual tunnel device, because tcpdump and sniffit give me an unknown media type error. Here's a tcpdump from the router box's ethernet device of a HTTP session (using lynx) to www.doomworld.com: 17:19:46.126297 xxx.xxx.xxx.xxx.1029 > 206.96.221.6.80: S 2549095564:2549095564(0) win 32120 (DF) 17:19:46.386142 206.96.221.6.80 > xxx.xxx.xxx.xxx.1029: S 1631828281:1631828281(0) ack 2549095565 win 30660 (DF) 17:19:46.386142 206.96.221.6.80 > xxx.xxx.xxx.xxx.1029: S 1631828281:1631828281(0) ack 2549095565 win 30660 (DF) 17:19:46.386142 xxx.xxx.xxx.xxx.1029 > 206.96.221.6.80: . ack 1 win 32120 (DF) 17:19:46.386142 xxx.xxx.xxx.xxx.1029 > 206.96.221.6.80: P 1:369(368) ack 1 win 32120 (DF) 17:19:46.685963 206.96.221.6.80 > xxx.xxx.xxx.xxx.1029: . ack 369 win 30660 (DF) 17:19:46.685963 206.96.221.6.80 > xxx.xxx.xxx.xxx.1029: . ack 369 win 30660 (DF) And the connection locks up. This happens every time. I don't have access to the Cisco so I can't dump traffic on the remote end of my tunnel. -- -=[ Count Zero / TBH - Jussi H?m?l?inen - email count@theblah.org ]=- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/