From owner-freebsd-net@freebsd.org Fri May 27 07:00:41 2016 Return-Path: Delivered-To: freebsd-net@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 0B053B4B39B for ; Fri, 27 May 2016 07:00:41 +0000 (UTC) (envelope-from sthaug@nethelp.no) Received: from bizet.nethelp.no (bizet.nethelp.no [195.1.209.33]) by mx1.freebsd.org (Postfix) with SMTP id 66E921B5D for ; Fri, 27 May 2016 07:00:39 +0000 (UTC) (envelope-from sthaug@nethelp.no) Received: (qmail 83570 invoked from network); 27 May 2016 06:53:55 -0000 Received: from bizet.nethelp.no (HELO localhost) (195.1.209.33) by bizet.nethelp.no with SMTP; 27 May 2016 06:53:55 -0000 Date: Fri, 27 May 2016 08:53:55 +0200 (CEST) Message-Id: <20160527.085355.74680254.sthaug@nethelp.no> To: mark.tinka@seacom.mu Cc: tinc@tinc-vpn.org, freebsd-net@freebsd.org, freebsd-questions@freebsd.org Subject: Re: IPv6, ULAs and FreeBSD,Re: IPv6, ULAs and FreeBSD From: sthaug@nethelp.no In-Reply-To: <016845dd-2c42-5aeb-f65d-02a6fb77acec@seacom.mu> References: <20160526193602.GF49239@box-fra-01.niklaas.eu> <20160526193602.GF49239@box-fra-01.niklaas.eu> <016845dd-2c42-5aeb-f65d-02a6fb77acec@seacom.mu> X-Mailer: Mew version 3.3 on Emacs 21.3 / Mule 5.0 (SAKAKI) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.22 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, 27 May 2016 07:00:41 -0000 > > Here lies the first problem. It seems that it's not legitimate to assign > > /96 subnets when using unique local addresses (ULAs). I was right > > getting some /48 subnet for my local IPv6 network; some easy way to get > > one generated randomly is http://unique-local-ipv6.com/ . But instead of > > assigning /96 subnets to each host, you must assign /64 subnets. I guess > > (but I am not sure because I have not found any reference that mentions > > this explicitly) you *must not* use any other subnet when dealing with > > ULAs. > > > > So I decided for the following two subnets for machine A and > > B respectively: fd16:dcc0:f4cc:1::/64 and fd16:dcc0:f4cc:2::/64. > > Interesting, I did not know that. > > I know that if you want SLAAC to work, you need to assign a /64 prefix. > > We use /112's for hosts but based on GUA's, and that works fine. I don't see any problem using ULA with for instance /124 netmask: lab1# ifconfig bce1.85 inet6 fd00:8c0:3::521/124 lab1# ifconfig bce1.85 bce1.85: flags=8843 metric 0 mtu 1500 options=103 ether 00:1a:64:94:d9:ae inet 172.17.85.1 netmask 0xffffff00 broadcast 172.17.85.255 inet6 fe80::21a:64ff:fe94:d9ae%bce1.85 prefixlen 64 scopeid 0x15 inet6 fd00:8c0:3::521 prefixlen 124 nd6 options=21 lab2# ifconfig bce1.85 inet6 fd00:8c0:3::522/124 lab2# ifconfig bce1.85 bce1.85: flags=8843 metric 0 mtu 1500 options=103 ether 00:1a:64:78:fa:ea inet 172.17.85.2 netmask 0xffffff00 broadcast 172.17.85.255 inet6 fe80::21a:64ff:fe78:faea%bce1.85 prefixlen 64 scopeid 0x13 inet6 fd00:8c0:3::522 prefixlen 124 nd6 options=21 lab2# ping6 fd00:8c0:3::521 PING6(56=40+8+8 bytes) fd00:8c0:3::522 --> fd00:8c0:3::521 16 bytes from fd00:8c0:3::521, icmp_seq=0 hlim=64 time=0.600 ms 96 bit works too: lab1# ifconfig bce1.85 inet6 fd00:8c0:3:1:1:1::1/96 lab2# ifconfig bce1.85 inet6 fd00:8c0:3:1:1:1::2/96 lab2# ping6 fd00:8c0:3:1:1:1::1 PING6(56=40+8+8 bytes) fd00:8c0:3:1:1:1:0:2 --> fd00:8c0:3:1:1:1:0:1 16 bytes from fd00:8c0:3:1:1:1:0:1, icmp_seq=0 hlim=64 time=0.585 ms Steinar Haug, Nethelp consulting, sthaug@nethelp.no