From owner-freebsd-net Tue Nov 27 9:21:16 2001 Delivered-To: freebsd-net@freebsd.org Received: from tomts20-srv.bellnexxia.net (tomts20.bellnexxia.net [209.226.175.74]) by hub.freebsd.org (Postfix) with ESMTP id BD13137B417 for ; Tue, 27 Nov 2001 09:21:04 -0800 (PST) Received: from xena.gsicomp.on.ca ([199.243.149.34]) by tomts20-srv.bellnexxia.net (InterMail vM.4.01.03.16 201-229-121-116-20010115) with ESMTP id <20011127172103.ZMVL25459.tomts20-srv.bellnexxia.net@xena.gsicomp.on.ca>; Tue, 27 Nov 2001 12:21:03 -0500 Received: from localhost (matt@localhost) by xena.gsicomp.on.ca (8.11.1/8.11.1) with ESMTP id fARHCoV57133; Tue, 27 Nov 2001 12:12:51 -0500 (EST) (envelope-from matt@xena.gsicomp.on.ca) Date: Tue, 27 Nov 2001 12:12:50 -0500 (EST) From: Matthew Emmerton To: Andre Oppermann , julian@elischer.org Cc: freebsd-net@FreeBSD.ORG Subject: Re: Very strange network behaviour - can anyone help me analyse tcpdump output? In-Reply-To: <3C036E9D.21808A44@pipeline.ch> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-net@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org On Tue, 27 Nov 2001, Andre Oppermann wrote: > Matthew Emmerton wrote: > > > > Hi all, > > > > In the continuing saga of IPSec over PPPoE for a retail POS environment that > > I'm maintaing, the problems seem to become more complex as time goes on. > > > > The network is quite simple: > > [ LAN #1 ] - [ FreeBSD Gateway #1 ] - [ ISP ] - [ FreeBSD Gateway #2 ] - [ > > LAN #2 ] > > > > Both LANs connect using PPPoE with the same ISP, and are one hop apart > > (according to traceroute). > > This smells like MTU problems. Try to set the MTU on your physical LAN > interfaces to something like 1480 or so any try again. That's what I thought too. I checked, and ppp is doing the TPC MSS fixup. Even after removing the gif/ipsec stuff that I was doing (less overhead, and converting this installation into a plain LAN-behind-NAT setup), the problem persists. I tried dropping the MTU on my LAN interface to 1200 (from 1500), but that didn't change anything. If my ISP installed a bunch of really buggy hardware, would that explain why this started happening recently without any changes on my side? -- Matt Emmerton To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message