From owner-freebsd-net@FreeBSD.ORG Fri Nov 19 08:52:16 2010 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 1A9BF1065670 for ; Fri, 19 Nov 2010 08:52:16 +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 50BD08FC1A for ; Fri, 19 Nov 2010 08:52:14 +0000 (UTC) Received: (qmail 6121 invoked from network); 19 Nov 2010 08:52:12 -0000 Received: from bizet.nethelp.no (HELO localhost) (195.1.209.33) by bizet.nethelp.no with SMTP; 19 Nov 2010 08:52:12 -0000 Date: Fri, 19 Nov 2010 09:52:12 +0100 (CET) Message-Id: <20101119.095212.74667071.sthaug@nethelp.no> To: siquijorphilips@gmail.com From: sthaug@nethelp.no In-Reply-To: References: 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 Cc: freebsd-net@freebsd.org Subject: Re: How to generate IPv6 RA without any prefixes? 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: Fri, 19 Nov 2010 08:52:16 -0000 > > In IPv6 it should be possible to generate a Router Advertisement which > > contains no prefix options (the idea being that I want the host to > > populate its default router list but nothing else). However, I cannot > > seem to get rtadvd to do this. > > > > If I start rtadvd with no /etc/rtadvd.conf file, it sends RAs with a > > prefix option corresponding to the IPv6 address of the interface. In > > the /etc/rtadvd.conf I can explicitly specify prefixes ("addr"), but > > I can't find any way to specify that no prefix options should be sent. > > > > Any suggestions? > > You mean to say that you want your router to act as the default IPv6 > gateway only advertising default route via RA and the IPv6 prefixes > are managed by other means such as DHCPv6 server? Correct. > Because by its the > only way I can think of with your case now. You can specify > 'pinfoflags' with 'l' in the /etc/rtadvd.conf to suppress the prefix > information option being advertised. Specifying a prefix ("addr") and "pinfoflags" with "l" makes rtadvd send RAs with a prefix info option option which contains the onlink flag. It certainly does not suppress the prefix info option. Specifying a prefix ("addr") and "pinfoflags" without "a" makes rtadvd send RAs with a prefix info option which does not contain the auto flag - this prevents SLAAC from taking place. I would like to get rtadvd to send RAs completely *without* a prefix info option. My Juniper routers at work can do this just fine... Steinar Haug, Nethelp consulting, sthaug@nethelp.no