From owner-freebsd-net@FreeBSD.ORG Sat Mar 19 08:34:42 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 B6BD11065676 for ; Sat, 19 Mar 2011 08:34:42 +0000 (UTC) (envelope-from eugene@zhegan.in) Received: from elf.hq.norma.perm.ru (mail.norman-vivat.ru [89.250.210.68]) by mx1.freebsd.org (Postfix) with ESMTP id 38D728FC0A for ; Sat, 19 Mar 2011 08:34:41 +0000 (UTC) Received: from bsdrookie.norma.com. (bsdrookie.hq.norma.perm.ru [192.168.7.246]) by elf.hq.norma.perm.ru (8.14.3/8.14.3) with ESMTP id p2J8YaVf095379 (version=TLSv1/SSLv3 cipher=DHE-RSA-CAMELLIA256-SHA bits=256 verify=NO) for ; Sat, 19 Mar 2011 13:34:36 +0500 (YEKT) (envelope-from eugene@zhegan.in) Message-ID: <4D846A9C.7000705@zhegan.in> Date: Sat, 19 Mar 2011 13:34:36 +0500 From: "Eugene M. Zheganin" User-Agent: Mozilla/5.0 (X11; U; FreeBSD i386; en-US; rv:1.9.2.8) Gecko/20100917 Thunderbird/3.1.2 MIME-Version: 1.0 To: freebsd-net@freebsd.org References: <4D8370AB.1070000@zhegan.in> <20110318.195636.74687196.sthaug@nethelp.no> In-Reply-To: <20110318.195636.74687196.sthaug@nethelp.no> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.3 (elf.hq.norma.perm.ru [192.168.3.10]); Sat, 19 Mar 2011 13:34:36 +0500 (YEKT) X-Callback: Sender verified by milter-callback 1.5.14 at elf.hq.norma.perm.ru. X-Callback-Status: relay [192.168.7.246] found in white list. X-Callback-Envelope-From: eugene@zhegan.in X-Spam-Status: No hits=-2.9 bayes=0.0000 testhits ALL_TRUSTED=-1, BAYES_00=-1.9 autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on elf.hq.norma.perm.ru Subject: Re: ipv6, stateful config and non-default prefixlen 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: Sat, 19 Mar 2011 08:34:43 -0000 Hi. On 18.03.2011 23:56, sthaug@nethelp.no wrote: > Are you using IA_PD or IA_NA on your DHCPv6 server? Since I didn't configure anything on a DHCPv6 server about PD, I assume I'm using NA. > rtadvd can give you the default router. > > DHCPv6 IA_NA gives you a single /128 address and no netmask. > > DHCPv6 IA_PD gives you a prefix (with the netmask of your choice), but > I don't know whether FreeBSD can (easily) use this. I don't see a relation between these 2 things. Prefix delegation is used to assign prefixes to client _routers_, without knowing about the topology. I'm configuring a _workstation_. I don't need a prefix to assign addresses to other computers, I don't have a network behind this workstation, I need to know about my prefix, and I have that information in ndp cache, although it is somehow useless. > As mentioned, DHCPv6 IA_PD gives you a prefix. And ISC dhclient can ask > for it, see the the -P option. "The Prefix Delegation options provide a mechanism for automateddelegation of IPv6 prefixes using the Dynamic Host Configuration Protocol (DHCP). This mechanism is intended for delegating a long-lived prefix from a delegating router to a requesting router, acrossan administrative boundary, where the delegating router does not require knowledge about the topology of the links in the network to which the prefixes will be assigned." And that's from RFC. > If you use DHCPv6 IA_NA, you receive a single /128 address (it is /128 > by definition, the DHCP answer doesn't include a netmask). That seems to be a mistake. Look what explanation I found in the ietf maillist: "Interface addresses are completely SEPARATE from routing information.Please do NOT confuse the two. This has been a source of confusion formany IPv6 implementors who know IPv4.The configuration of addresses for an interface MUST NOT be tied to the configuration of prefix information for routing. Just because a prefix is on a link, does not mean the interface necessarily has an address for that prefix (it may have none, 1, or many). Just because an interface has an address, does not mean that the system has any prefix information for a prefix that "contains" that address. Prefix information and addresses assigned to interfaces are completely separate." So it's just an address. Not a /128, just an address. > You should *not* expect to reach other computers on the link through such a /128 > address So, in other words, DHCPv6 is useless. No, I don't think so. I have a bunch of windows on the same link, working with the same DHCPv6 server, and doing just fine. And that's sad, because I used to think that FreeBSD is always a queen of the network, far ahead of the non-truly-networked OS bunch. I'm still hoping that this /64 prefix issue is related to my low knowledge. P.S. And I know that autoconfiguration won't work on a link with /120. And of course, THAT is the reason why I'm using the DHCPv6. Eugene.