From owner-freebsd-net Wed Aug 28 12:34:42 2002 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 D2B4A37B49F for ; Wed, 28 Aug 2002 12:34:26 -0700 (PDT) Received: from 66-162-33-178.gen.twtelecom.net (66-162-33-178.gen.twtelecom.net [66.162.33.178]) by mx1.FreeBSD.org (Postfix) with ESMTP id 6088543E65 for ; Wed, 28 Aug 2002 12:34:26 -0700 (PDT) (envelope-from jeff@expertcity.com) Received: from [10.4.1.134] (helo=expertcity.com) by 66-162-33-178.gen.twtelecom.net with esmtp (Exim 3.22 #4) id 17k8a9-0003TG-00; Wed, 28 Aug 2002 12:34:25 -0700 Message-ID: <3D6D257D.5080300@expertcity.com> Date: Wed, 28 Aug 2002 12:33:17 -0700 From: Jeff Behl User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.1) Gecko/20020826 X-Accept-Language: en-us, en MIME-Version: 1.0 To: net@freebsd.org Cc: Julian Elischer Subject: Re: MTU not working? References: Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit 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 Just an FYI, but I have opened a bug report on this: http://www.freebsd.org/cgi/query-pr.cgi?pr=42137 so hopefully someone with the know-how can come up with a fix. jeff Julian Elischer wrote: > > On Mon, 19 Aug 2002, Steve Francis wrote: > > >>Allow me to respond for Jeff (we work at same place, and have both been >>looking this issue) >> >>ICMP's being blocked are the most common explanation for this - but >>this is not the case here. >> >>tcpdump run on the server system shows the ICMP fragmention required - >>DF bit set messages being received, and - the irrefutable proof that it >>is not an ICMP filtering issue -the FreeBSD system DOES lower the MTU >>for that host's cloned route to the value specified in the ICMP (1420 >>in the snippet below). New packets are segmented to sizes <= the new >>MTU, but it continues resend the original packet over and over, in the >>original 1500 byte size. >> >>So I still say FreeBSD has broken pMTU-D code. >> >>This is reproducible at will, so we can collect whatever info anyone >>wants. >> >> > > > Yes > tcp needs to forget it ever sent that data, and refactor the entire > transmit window. > > I'd agree this is a bug if it's reproducible by others too. > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message