From owner-freebsd-hackers Wed Dec 2 12:59:13 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id MAA03954 for freebsd-hackers-outgoing; Wed, 2 Dec 1998 12:59:13 -0800 (PST) (envelope-from owner-freebsd-hackers@FreeBSD.ORG) Received: from gvr.gvr.org (gvr.gvr.org [194.151.74.97]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id MAA03924 for ; Wed, 2 Dec 1998 12:59:00 -0800 (PST) (envelope-from guido@gvr.org) Received: (from guido@localhost) by gvr.gvr.org (8.8.8/8.8.5) id VAA23085; Wed, 2 Dec 1998 21:57:30 +0100 (MET) Message-ID: <19981202215730.B23018@gvr.org> Date: Wed, 2 Dec 1998 21:57:30 +0100 From: Guido van Rooij To: Nate Williams , Daniel Eischen Cc: dillon@apollo.backplane.com, hackers@FreeBSD.ORG, luigi@labinfo.iet.unipi.it Subject: Re: TCP bug References: <199812021626.LAA27156@pcnet1.pcnet.com> <199812021636.JAA06068@mt.sri.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 0.93.2i In-Reply-To: <199812021636.JAA06068@mt.sri.com>; from Nate Williams on Wed, Dec 02, 1998 at 09:36:05AM -0700 Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Wed, Dec 02, 1998 at 09:36:05AM -0700, Nate Williams wrote: > No, the router can, but any machines hung off it's ethernet can't. On a > whim (based on a hint I got from Karl Peilorz) I changed the MTU on the > router (which is running SLIP to get to the net) from 552 to 1500, and > now things work. > > The strange things is that that the mtu of the SLIP interface if/was 552 > and all traffic that originated on that box was fine, and the mtu on the > ethernet interface was 1500, and traffic generated from there did not > work. > > I would have thought that you wouldn't need to fragment any packets that > had a mtu of 552 to stick it on an ethernet with an mtu of 1500. > > I need to lookmore into this... In my previous mail I already stated why things can go wrong if the www server on the internet has a badly configured packet filter. In your case it seems that your router is badly configured. Does it filter out ICMP ICMP_UNREACH_NEEDFRAG pakcets from the ethernet to the ouside, but not from your router to the outside? -Guido To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message