From owner-freebsd-net@FreeBSD.ORG Wed Jun 8 20:02:47 2011 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 0B168106566B for ; Wed, 8 Jun 2011 20:02:47 +0000 (UTC) (envelope-from mjl@luckie.org.nz) Received: from mailfilter4.ihug.co.nz (mailfilter4.ihug.co.nz [203.109.136.4]) by mx1.freebsd.org (Postfix) with ESMTP id 90CE08FC1A for ; Wed, 8 Jun 2011 20:02:46 +0000 (UTC) X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: Av0EAPLU7012XDZi/2dsb2JhbABTG6YZeIhxviuGIwSRG4tShA4 X-IronPort-AV: E=Sophos;i="4.65,339,1304251200"; d="scan'208";a="357038623" Received: from 118-92-54-98.dsl.dyn.ihug.co.nz (HELO spandex.luckie.org.nz) ([118.92.54.98]) by cust.filter4.content.vf.net.nz with ESMTP/TLS/DHE-RSA-AES256-SHA; 09 Jun 2011 08:02:44 +1200 Received: from d18.luckie.org.nz ([192.168.1.18] helo=mylar.luckie.org.nz) by spandex.luckie.org.nz with esmtpsa (TLSv1:CAMELLIA256-SHA:256) (Exim 4.76 (FreeBSD)) (envelope-from ) id 1QUOxf-0003I0-Vv; Thu, 09 Jun 2011 08:02:43 +1200 Message-ID: <4DEFD5CB.7060703@luckie.org.nz> Date: Thu, 09 Jun 2011 08:04:27 +1200 From: Matthew Luckie User-Agent: Mozilla/5.0 (X11; U; FreeBSD i386; en-US; rv:1.9.2.17) Gecko/20110429 Thunderbird/3.1.10 MIME-Version: 1.0 To: "Bjoern A. Zeeb" References: <20110608143359.GA478@spandex.luckie.org.nz> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: freebsd-net@freebsd.org Subject: Re: FreeBSD, IPv6 and World IPv6 Day 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: Wed, 08 Jun 2011 20:02:47 -0000 >>> I found measurement results on this website: >>> http://hide.dnsalias.net/aaaa/worldipv6day.cgi >> >> Some more results: >> >> http://www.wand.net.nz/~mluckie/ipv6day/ > > Interesting. Did you post on the v6 lists as well? Just on ipv6-techsig@listserv.internetnz.net.nz Feel free to forward on to other lists if you think its useful. >> http://www.freebsd.org/cgi/query-pr.cgi?pr=145733 > > That's the frag6 ipfw iusse, right? Well actually 3 issues. I have this > is open in my other window today after having stared at it for too long. > > BTW. does anyone have any idea what kind of systems generate these packets? > Does anyone have packet dumps of them? A couple of people would be > curious to have/see that. In terms of systems that will respond to a PTB by sending IPv6 fragments rather than sending smaller TCP packets: http://www.kddi.com http://dream.jp/ http://www.ubc.ca/ http://www.goneo.de/ http://www.nict.go.jp/ (I can go on further if you want) If I had to guess at what OS sends these packets I'd guess netbsd or openbsd but I've never looked. To reproduce above, use http://www.wand.net.nz/scamper/scamper-cvs-20110608.tar.gz http://www.wand.net.nz/scamper/pmtud Use -M 1480, that will cause the last fragment to be small and trigger one of the bugs in the PR. In terms of systems that will respond to a PTB with nhmtu < 1280, it seems most follow the advice in RFC2460 and send packets with a fragmentation header without fragmenting the packet. Use -M 576 with your scamper command line.