From owner-freebsd-net@FreeBSD.ORG Sun Apr 13 17:24:46 2008 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 2D6881065675 for ; Sun, 13 Apr 2008 17:24:46 +0000 (UTC) (envelope-from mike@sentex.net) Received: from smarthost1.sentex.ca (smarthost1.sentex.ca [64.7.153.18]) by mx1.freebsd.org (Postfix) with ESMTP id C86888FC19 for ; Sun, 13 Apr 2008 17:24:45 +0000 (UTC) (envelope-from mike@sentex.net) Received: from lava.sentex.ca (pyroxene.sentex.ca [199.212.134.18]) by smarthost1.sentex.ca (8.14.2/8.14.2) with ESMTP id m3DGvurZ095239 for ; Sun, 13 Apr 2008 12:57:56 -0400 (EDT) (envelope-from mike@sentex.net) Received: from mdt-xp.sentex.net (simeon.sentex.ca [192.168.43.27]) by lava.sentex.ca (8.13.8/8.13.3) with ESMTP id m3DGvuG6039297 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Sun, 13 Apr 2008 12:57:56 -0400 (EDT) (envelope-from mike@sentex.net) Message-Id: <200804131657.m3DGvuG6039297@lava.sentex.ca> X-Mailer: QUALCOMM Windows Eudora Version 7.1.0.9 Date: Sun, 13 Apr 2008 12:58:03 -0400 To: freebsd-net@freebsd.org From: Mike Tancsa Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; format=flowed Subject: route change and MTU 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, 13 Apr 2008 17:24:46 -0000 This sort of seems like a bug, but not sure If I had 2 interfaces, one tun1, pppoe with an MTU of 1492, and one ethernet, a normal MTU of 1500. if the default route was via tun1, and I did a route change default the MTU stays at 1492 e.g. on my RELENG_7 box 0[cage]# route add 1.1.1.1/30 64.7.157.1 add net 1.1.1.1: gateway 64.7.157.1 0[cage]# route get 1.1.1.1 route to: 1.1.1.1 destination: 1.1.1.0 mask: 255.255.255.252 gateway: dslborder1.sentex.ca interface: tun0 flags: recvpipe sendpipe ssthresh rtt,msec rttvar hopcount mtu expire 0 0 0 0 0 0 1492 0 This is correct. The MTU on the PPPoE interface is 1492 0[cage]# route change 1.1.1.1/30 192.168.0.3 change net 1.1.1.1: gateway 192.168.0.3 0[cage]# route get 1.1.1.1 route to: 1.1.1.1 destination: 1.1.1.0 mask: 255.255.255.252 gateway: 192.168.0.3 interface: bge0 flags: recvpipe sendpipe ssthresh rtt,msec rttvar hopcount mtu expire 0 0 0 0 0 0 1492 0 0[cage]# ifconfig bge0 bge0: flags=8843 metric 0 mtu 1500 options=9b ether 00:10:18:14:15:43 inet 192.168.0.12 netmask 0xffffff00 broadcast 192.168.0.255 media: Ethernet autoselect (100baseTX ) status: active 0[cage]# The MTU should be 1500 after the route change no ? ---Mike -------------------------------------------------------------------- Mike Tancsa, tel +1 519 651 3400 Sentex Communications, mike@sentex.net Providing Internet since 1994 www.sentex.net Cambridge, Ontario Canada www.sentex.net/mike