From owner-freebsd-net@FreeBSD.ORG Thu May 19 10:20:43 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 81F281065670 for ; Thu, 19 May 2011 10:20:43 +0000 (UTC) (envelope-from hrs@FreeBSD.org) Received: from mail.vlsi.ee.noda.tus.ac.jp (sekine00.ee.noda.sut.ac.jp [133.31.107.40]) by mx1.freebsd.org (Postfix) with ESMTP id 3F3418FC12 for ; Thu, 19 May 2011 10:20:42 +0000 (UTC) Received: from alph.allbsd.org (p2237-ipbf904funabasi.chiba.ocn.ne.jp [122.26.37.237]) (user=hrs mech=DIGEST-MD5 bits=128) by mail.vlsi.ee.noda.tus.ac.jp (8.14.4/8.14.4) with ESMTP id p4JAKJEo079828 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Thu, 19 May 2011 19:20:30 +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 p4JAK7Ei061227; Thu, 19 May 2011 19:20:09 +0900 (JST) (envelope-from hrs@FreeBSD.org) Date: Thu, 19 May 2011 19:07:28 +0900 (JST) Message-Id: <20110519.190728.881895202152708492.hrs@allbsd.org> To: spork@bway.net From: Hiroki Sato In-Reply-To: References: <20110517.174313.868674729938461030.hrs@allbsd.org> X-PGPkey-fingerprint: BDB3 443F A5DD B3D0 A530 FFD7 4F2C D3D8 2793 CF2D X-Mailer: Mew version 6.3 on Emacs 23.1 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Multipart/Signed; protocol="application/pgp-signature"; micalg=pgp-sha1; boundary="--Security_Multipart(Thu_May_19_19_07_28_2011_851)--" Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.2.5 (mail.vlsi.ee.noda.tus.ac.jp [133.31.107.40]); Thu, 19 May 2011 19:20:30 +0900 (JST) X-Spam-Status: No, score=6.1 required=14.0 tests=BAYES_50, CONTENT_TYPE_PRESENT, RCVD_IN_PBL, RCVD_IN_RP_RNBL, SPF_SOFTFAIL, X_MAILER_PRESENT autolearn=no version=3.3.1 X-Spam-Level: ****** X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.vlsi.ee.noda.tus.ac.jp Cc: freebsd-net@FreeBSD.org Subject: Re: IPv6 alias masks/masks for routed aliases 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: Thu, 19 May 2011 10:20:43 -0000 ----Security_Multipart(Thu_May_19_19_07_28_2011_851)-- Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Charles Sprickman wrote in : sp> On Tue, 17 May 2011, Hiroki Sato wrote: sp> sp> > Charles Sprickman wrote sp> > in sp> > : sp> > sp> > sp> First, the easy one. For IPv6 aliases, what is the proper subnet? sp> > sp> > Normally it is a /64. See also Section 2.5.4 in RFC 4291. sp> sp> My understanding was that a /64 was a common subnet since it's the sp> minimum size required for host autoconfiguration. What I'm really sp> looking for is the FreeBSD-specific recommendation for configuring sp> aliases - I understand that I'll probably have a /64 on the LAN, but sp> when setting a netmask on a single IPv6 alias are the rules different sp> than they are for IPv4? So if I've got a lan block that's a /64 and I sp> configure an alias on a FreeBSD host, do I give the alias the lan sp> subnet (/64) or a host subnet (/128)? For IPv4, I believe that it sp> should always be the host subnet (/32). There is no FreeBSD-specific configuration. The recommendation is /64 because various IPv6 specs assume /64 prefix length for a global unicast address on a host and FreeBSD implementation supports configuration of multiple /64 addresses on a single interface. There is no reason to use /128 or ones longer than 64 while you can configure a GUA with such a longer prefix. sp> The current setup looks like this on the ISP side: I am still not sure of the network topology. Something like this? (ISP) | |10.[123456].0.0 (router) |10.1.0.1/27 | (hosts) 10.1.0.x/27 10.2.0.2/28 10.2.0.3/32 : Hmm, I may misunderstand something. If this diagram is correct, I am wondering why the router has 10.[123456].0.0 addresses on the WAN side, not on the FE0/1 side. I feel like simply configuring 10.[123456].0.1 on the LAN side instead and an address on the ISP side which can communicate ISP's router would work. -- Hiroki ----Security_Multipart(Thu_May_19_19_07_28_2011_851)-- Content-Type: application/pgp-signature Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (FreeBSD) iEYEABECAAYFAk3U6+AACgkQTyzT2CeTzy3jjwCeMDX2uC40TapE4toeClSjGH2x jt4An2pGqEIaSd+l2bv4c9O6B/p3KGTP =MzT6 -----END PGP SIGNATURE----- ----Security_Multipart(Thu_May_19_19_07_28_2011_851)----