From owner-freebsd-net@FreeBSD.ORG Wed Dec 14 00:42:25 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 3DA771065675 for ; Wed, 14 Dec 2011 00:42:25 +0000 (UTC) (envelope-from hrs@FreeBSD.org) Received: from mail.allbsd.org (gatekeeper-int.allbsd.org [IPv6:2001:2f0:104:e002::2]) by mx1.freebsd.org (Postfix) with ESMTP id F10F98FC0C for ; Wed, 14 Dec 2011 00:42:23 +0000 (UTC) Received: from alph.allbsd.org ([IPv6:2001:2f0:104:e010:862b:2bff:febc:8956]) (authenticated bits=128) by mail.allbsd.org (8.14.4/8.14.4) with ESMTP id pBE0g7VF014873; Wed, 14 Dec 2011 09:42:18 +0900 (JST) (envelope-from hrs@FreeBSD.org) Received: from localhost (localhost [IPv6:::1]) (authenticated bits=0) by alph.allbsd.org (8.14.4/8.14.4) with ESMTP id pBE0g43Y083854; Wed, 14 Dec 2011 09:42:06 +0900 (JST) (envelope-from hrs@FreeBSD.org) Date: Wed, 14 Dec 2011 09:41:51 +0900 (JST) Message-Id: <20111214.094151.1901872428047005963.hrs@allbsd.org> To: mrossi@swin.edu.au From: Hiroki Sato In-Reply-To: <4EE7CDBE.1090605@swin.edu.au> References: <58FFF22D-6578-447D-AAC0-9673057DAD84@gsoft.com.au> <4EE7CDBE.1090605@swin.edu.au> X-PGPkey-fingerprint: BDB3 443F A5DD B3D0 A530 FFD7 4F2C D3D8 2793 CF2D X-Mailer: Mew version 6.3.51 on Emacs 23.3 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Multipart/Signed; protocol="application/pgp-signature"; micalg=pgp-sha1; boundary="--Security_Multipart(Wed_Dec_14_09_41_51_2011_589)--" Content-Transfer-Encoding: 7bit X-Virus-Scanned: clamav-milter 0.97 at gatekeeper.allbsd.org X-Virus-Status: Clean X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.3 (mail.allbsd.org [IPv6:2001:2f0:104:e001::32]); Wed, 14 Dec 2011 09:42:21 +0900 (JST) X-Spam-Status: No, score=-104.6 required=13.0 tests=BAYES_00, CONTENT_TYPE_PRESENT, RDNS_NONE, SPF_SOFTFAIL, USER_IN_WHITELIST autolearn=no version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on gatekeeper.allbsd.org Cc: doconnor@gsoft.com.au, freebsd-net@FreeBSD.org Subject: Re: FreeBSD 8 as an IPv6 router 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, 14 Dec 2011 00:42:25 -0000 ----Security_Multipart(Wed_Dec_14_09_41_51_2011_589)-- Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Mattia Rossi wrote in <4EE7CDBE.1090605@swin.edu.au>: mr> Ok, this is something I always get a bit confused with. I understand mr> that it's the right clean thing to set up a /64 on the interface which mr> sends router advertisements, but I also would expect by nature, that mr> whatever prefixlength you chose on the interface, rtadvd would simply mr> grab the lowest /64 prefix out of the configured one to send router mr> advertisements out. mr> mr> The idea there is, that you might use this router for multiple mr> subnets, and have a single default route. mr> mr> Now of course to do that you'd need to configure rtadvd.conf, so I mr> guess the whole thing missing here is a bit of documentation which mr> says, that if you don't configure rtadvd via rtadvd.conf you're not mr> allowed to be lazy and configure any prefix on the interface and mr> expect rtadvd to do the right thing. mr> mr> It seems to me, that a lot of people (including me) would expect that, mr> so maybe some info about that wouldn't be to bad. I do not think it is a good idea that the rtadvd daemon automatically splits prefixes shorter than 64 to ones with just 64. "Which prefix should be advertised" is one of things which a sysadmin must specify explicitly when it receives prefixes shorter than 64 via IA-PD or something, and it should match the actual subnet structure. A simple way to do so is to assign an address onto eth0, in his example, with desired /64 subnet prefix from the delegated (shorter) prefix, and run rtadvd with no configuration file. This is the expected scenario. A /60 address assigned on eth0 does not work as a default router address for multiple /64 subnets anyway... This trouble is caused by misconfiguration of sla-len and non-/64 prefix is assigned unexpectedly to eth0. If all of the configuration were correct rtadvd.conf was not needed in the first place, and even if split /64 prefixes were automatically advertised by rtadvd at that time the situation would not got better. -- Hiroki ----Security_Multipart(Wed_Dec_14_09_41_51_2011_589)-- Content-Type: application/pgp-signature Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (FreeBSD) iEYEABECAAYFAk7n8M8ACgkQTyzT2CeTzy3yxACg1g296S7W3Tjdt/zo77vN9kt1 DngAoJBPU2Qhb4gSW61sW+Nh933gGb2/ =ai9n -----END PGP SIGNATURE----- ----Security_Multipart(Wed_Dec_14_09_41_51_2011_589)----