From owner-freebsd-questions@FreeBSD.ORG Mon Jan 16 19:17:02 2012 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id BE7FE106564A for ; Mon, 16 Jan 2012 19:17:02 +0000 (UTC) (envelope-from mokomull@gmail.com) Received: from mail-we0-f182.google.com (mail-we0-f182.google.com [74.125.82.182]) by mx1.freebsd.org (Postfix) with ESMTP id 51CF38FC13 for ; Mon, 16 Jan 2012 19:17:01 +0000 (UTC) Received: by werg1 with SMTP id g1so2059540wer.13 for ; Mon, 16 Jan 2012 11:17:01 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=dbHacbbS+h3RlMmeN/tz/XshE9vKkZr4vt4nk87m5pY=; b=nRGmI3zcM/o9Ljfrcr8Z0zklcxp3EXNshuS4KUvvJWi5cs8RjFHaSRNmh8oQRQegl7 XJeHnky5My/nIr0ShD89JxDa1ZzTkgjgqEE/ttrXy7DnmF9+XWUf2M8P5J3tx/QEmTMx ssDXNun5JOe9gTRGGz8BiDNlGYdCeENdyY05c= MIME-Version: 1.0 Received: by 10.216.136.34 with SMTP id v34mr4375564wei.13.1326741379057; Mon, 16 Jan 2012 11:16:19 -0800 (PST) Received: by 10.223.156.65 with HTTP; Mon, 16 Jan 2012 11:16:19 -0800 (PST) In-Reply-To: <4F12F04B.2080504@macfreek.nl> References: <4F12F04B.2080504@macfreek.nl> Date: Mon, 16 Jan 2012 11:16:19 -0800 Message-ID: From: Matt Mullins To: Freek Dijkstra Content-Type: text/plain; charset=ISO-8859-1 Cc: freebsd-questions@freebsd.org Subject: Re: Disable auto_linklocal X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 16 Jan 2012 19:17:02 -0000 On Sun, Jan 15, 2012 at 7:27 AM, Freek Dijkstra wrote: > The link-local addresses don't really harm, but I found them confusing, > as the host is running as a router, and rtadv announces the link-local > address by default. IPv6-standards-wise, this is the correct thing to do. Router advertisements should contain link-local source addresses and advertise the link-local address as the router; the globally-routable prefix that is being advertised is a completely different field in those messages. I'm not too sure of the reasons behind this, other than eliminating some need for carp(4): you can have multiple routers on a subnet and if one goes down, clients will just pick up the other's router advertisements. It's atypical that one would want to disable link-local addressing, since it's one of the core differences from IPv4 that adds some benefit and flexibility. References: http://tools.ietf.org/html/rfc4861#section-4.2 Source Address MUST be the link-local address assigned to the interface from which this message is sent." -- Matt Mullins