From owner-freebsd-net@FreeBSD.ORG Sun Nov 2 06:05:30 2003 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 77ECF16A4CE for ; Sun, 2 Nov 2003 06:05:30 -0800 (PST) Received: from dastardly.newsbastards.org.72.27.172.IN-addr.ARPA.NOSPAM.dyndns.dk (does-d9b91910.pool.mediaWays.net [217.185.25.16]) by mx1.FreeBSD.org (Postfix) with ESMTP id 174AE43FAF for ; Sun, 2 Nov 2003 06:04:32 -0800 (PST) (envelope-from bounce@NOSPAM.dyndns.dk) Received: from NOSPAM.spam.NOSPAM.spam.NOSPAM.dyndns.dk (NOSPAM.spam.NOSPAM.spam.NOSPAM.dyndns.dk [2002:d9b9:1910:0:200:c0ff:fefc:19aa] (may be forged)) (8.11.6/8.11.6-SPAMMERS-DeLiGHt) with ESMTP id hA2E3qb82879 verified NO) for ; Sun, 2 Nov 2003 15:03:54 +0100 (CET) (envelope-from bounce@NOSPAM.dyndns.dk) Received: (from beer@localhost)hA2E3OE48213; Sun, 2 Nov 2003 15:03:24 +0100 (CET) (envelope-from bounce@NOSPAM.dyndns.dk) Date: Sun, 2 Nov 2003 15:03:24 +0100 (CET) Message-Id: <200311021403.hA2E3OE48213@NOSPAM.spam.NOSPAM.spam.NOSPAM.dyndns.dk> X-Authentication-Warning: NOSPAM.spam.NOSPAM.spam.NOSPAM.dyndns.dk: beer set sender to bounce@NOSPAM.dyndns.dk using -f From: Barry Bouwsma To: FreeBSD Networking Nerds Subject: IPv6 autoconf addresses with changing RAs... X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 02 Nov 2003 14:05:30 -0000 [Drop hostname part of IPv6-only address above to obtain IPv4-capable e-mail, or just drop me from the recipients and I'll catch up from the archives, since I'm too much offline and replies will probably go astray anyways] Apologies if this has been asked before; I've only zgrep'ed this year's archives for `autoconf' and see nothing comparable -- only something from beginning-October-or-so concerning autoconf IPv6 addresses learned from multiple routers -- a setup which I don't want any so-called `solution' to my query to adversely affect. I have one IPv6 machine behind a second, which second machine for historical reasons has an IPv6 prefix/address that occasionally changes. After this happens, the first host-only machine receives an additional autoconf IPv6 address, but it still retains the old (now obsolete) IPv6 autoconf address it had learned from this same router. The machines are running kernels RELENG_4 from late-September-ish. Userland varies horribly. What I want to happen, is that when the new IPv6 address is autoconf'ed, the old one should disappear from the interface. (I've been too impatient to watch if it disappears after time, during which time I cannot reach the router's new address or the default route, as the old prefix which it had is no longer present thanks to my hacked scripts. If I manually delete the original IPv6 address, it seems that things work.) [Historical reasons background: I receive a different IPv4 address via dial-in PPP each time I go online. From this I derive a 6to4 2002:... prefix that I use for IPv6 network address. The router machine (the ppp machine) is poked to deliver an RA at time of new address configuration. I no longer bother to delete this 6to4 address when going offline, but next time I go online, I get a new IPv6 prefix (deleting the old one), that the host machine learns.] Is there a way of being automagically notified when a RA is heard/a new IPv6 address is autoconf'ed, so I can trigger a script to check and if needed, delete the old IPv6 address? Or must I periodically check the IPv6 addresses for any changes? Or, is it possible for the kernel itself, in my case -- a single router, to be different from the case posted a month ago of two routers on the same net -- to automagically dispose of the old previously-autoconf'ed IPv6 address upon receiving a new RA broadcast? Perhaps to be controlled by a sysctl knob, to allow one to choose between a single changing RA, or RAs from multiple machines where IPv6 address-hopping is unwanted? The advantage of being notified of such an RA change (instead of it just resulting quietly in an IPv6 address change) is that I could at the same time trigger a dynamic DNS update. At present, it seems I need to do both IPv6 address fudging and dynamic DNS updates with periodic polling of the interface status. Thanks, Barry Bouwsma still unclear on the concept