From owner-freebsd-net@FreeBSD.ORG Fri Dec 26 15:15:09 2003 Return-Path: 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 2E9E516A4CE for ; Fri, 26 Dec 2003 15:15:09 -0800 (PST) Received: from tenebras.com (laptop.tenebras.com [66.92.188.18]) by mx1.FreeBSD.org (Postfix) with SMTP id 4A99643D1D for ; Fri, 26 Dec 2003 15:15:07 -0800 (PST) (envelope-from kudzu@tenebras.com) Received: (qmail 68503 invoked from network); 26 Dec 2003 23:15:06 -0000 Received: from sapphire.tenebras.com (HELO tenebras.com) (192.168.188.241) by laptop.tenebras.com with SMTP; 26 Dec 2003 23:15:06 -0000 Message-ID: <3FECC0F7.6090309@tenebras.com> Date: Fri, 26 Dec 2003 15:15:03 -0800 From: Michael Sierchio User-Agent: Mozilla/5.0 (X11; U; Linux i386; en-US; rv:1.5) Gecko/20031007 X-Accept-Language: en-us, zh-tw, zh-cn, fr, en, de-de MIME-Version: 1.0 To: Stephane Raimbault References: In-Reply-To: Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit cc: net@freebsd.org Subject: Re: VLAN MTU problem in 4.9 ? X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 26 Dec 2003 23:15:09 -0000 Stephane Raimbault wrote: > So it seems that when I specify a ping of greater then 1468 the pings > stop responding to the vlan interface on the freebsd router? > > I also did a tcpdump while doing these pings from the freebsd router and > it doesn't see any packets when specifying a ping of 1469, but it sees > the ping with pkt size specified to 1468. > > Any thoughts on this problem that I'm having? Any other data I can > provider perhaps? DF? Size of tagged frames? Recall that "packet size" perhaps not what you think, also. Have you read the vlan man page, specifically: Note: Unless marked as having native support for vlan, the above drivers don't inform the vlan driver about their long frame handling capability. Just increase the MTU of a vlan interface if it appears to be lower than 1500 bytes after attaching to a parent known to support long frames. But you invite speculation -- a raw tcpdump (-nqvv or so) would be nice.