From owner-freebsd-net@FreeBSD.ORG Sun Sep 11 22:48:28 2005 Return-Path: X-Original-To: freebsd-net@freebsd.org Delivered-To: freebsd-net@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 9E3A016A41F for ; Sun, 11 Sep 2005 22:48:28 +0000 (GMT) (envelope-from spork@bway.net) Received: from mail.bway.net (xena.bway.net [216.220.96.26]) by mx1.FreeBSD.org (Postfix) with ESMTP id 1B4C943D46 for ; Sun, 11 Sep 2005 22:48:27 +0000 (GMT) (envelope-from spork@bway.net) Received: (qmail 46630 invoked by uid 0); 11 Sep 2005 22:48:26 -0000 Received: from unknown (HELO white.nat.fasttrackmonkey.com) (spork@bway.net@216.220.116.154) by smtp.bway.net with (DHE-RSA-AES256-SHA encrypted) SMTP; 11 Sep 2005 22:48:26 -0000 Date: Sun, 11 Sep 2005 18:48:25 -0400 (EDT) From: Charles Sprickman X-X-Sender: spork@white.nat.fasttrackmonkey.com To: "Julian H. Stacey" In-Reply-To: <200509100930.j8A9UoHN062107@fire.jhs.private> Message-ID: References: <200509100930.j8A9UoHN062107@fire.jhs.private> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Cc: freebsd-net@freebsd.org Subject: Re: PPPoE and UDP fragmentation X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 11 Sep 2005 22:48:28 -0000 On Sat, 10 Sep 2005, Julian H. Stacey wrote: >> -Are there any tunables at either end (both hosts are FreeBSD 4.11 p11) to >> alter how fragmented packets are re-assembled? > > /usr/ports/net/tcpmssd > An MTU adapter. Apparently not needed on FreeBSD-5 but I mean to > install it on my FreeBSD-4 DSL gateways when I find time to think if it might > have any implications re ipfw & security. I don't think that does anything to UDP, it just digs into tcp and "fixes up" the MSS by altering it on outgoing packets. I'm looking to further understand UDP fragmentation and why a host might ignore fragments, and who along the way is actually doing the fragmentation. My current "fix" is just to set the interface MTU on the sending box to 1492, and that works well, but I'd really like to understand why it fails without that. Thanks! Charles > -- > Julian Stacey. Consultant Unix Net & Sys. Eng., Munich. http://berklix.com > Mail Ascii not HTML. Ihr Rauch = meine allergischen Kopfschmerzen. >