From owner-freebsd-net@FreeBSD.ORG Wed Mar 13 17:13:20 2013 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by hub.freebsd.org (Postfix) with ESMTP id 1E822AC0 for ; Wed, 13 Mar 2013 17:13:20 +0000 (UTC) (envelope-from Mark.Martinec+freebsd@ijs.si) Received: from mail.ijs.si (mail.ijs.si [193.2.4.66]) by mx1.freebsd.org (Postfix) with ESMTP id CC10D850 for ; Wed, 13 Mar 2013 17:13:17 +0000 (UTC) Received: from amavis-proxy-ori.ijs.si (localhost [IPv6:::1]) by mail.ijs.si (Postfix) with ESMTP id 3ZR03v6T1NzGMp8 for ; Wed, 13 Mar 2013 18:12:43 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ijs.si; h= message-id:content-transfer-encoding:content-type:content-type :mime-version:in-reply-to:references:user-agent:date:date :subject:subject:organization:from:from:received:received :received:vbr-info; s=jakla2; t=1363194757; x=1365786758; bh=9z9 BMtra0KqiPe7+GeRLiKsV0NevRObq1oR2NgruCh0=; b=fW/Vko67KnEK0LbU1x2 9DHMSXSsFBeoR9NWAEBdfCxBxq9FMLDEegb+VgSdaecQve3+DAOkUrw0mMZMmaRS suiE1IlGcjqoYIVQAAr2EASUaAmzQV7oFZe1bpMplpaaad3dL51Dbi3IBrQoF0x8 WvL/0pan4PJiF9d0HlGhpkS4= VBR-Info: md=ijs.si; mc=all; mv=dwl.spamhaus.org; X-Virus-Scanned: amavisd-new at ijs.si Received: from mail.ijs.si ([IPv6:::1]) by amavis-proxy-ori.ijs.si (mail.ijs.si [IPv6:::1]) (amavisd-new, port 10012) with ESMTP id 4Mzi1R2J_tR0 for ; Wed, 13 Mar 2013 18:12:37 +0100 (CET) Received: from mildred.ijs.si (mailbox.ijs.si [IPv6:2001:1470:ff80::143:1]) by mail.ijs.si (Postfix) with ESMTP for ; Wed, 13 Mar 2013 18:12:37 +0100 (CET) Received: from neli.ijs.si (neli.ijs.si [IPv6:2001:1470:ff80:88:21c:c0ff:feb1:8c91]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mildred.ijs.si (Postfix) with ESMTPSA id DA556B04 for ; Wed, 13 Mar 2013 18:12:36 +0100 (CET) From: Mark Martinec Organization: J. Stefan Institute To: freebsd-net@freebsd.org Subject: Re: ipv6 default router Operation not permitted Date: Wed, 13 Mar 2013 18:12:36 +0100 User-Agent: KMail/1.13.7 (FreeBSD/9.1-STABLE; KDE/4.9.5; amd64; ; ) References: <20130312225018.GA13589@defiant.konundrum.org> <201303131659.04074.Mark.Martinec+freebsd@ijs.si> <20130313162700.GD18992@defiant.konundrum.org> In-Reply-To: <20130313162700.GD18992@defiant.konundrum.org> MIME-Version: 1.0 Content-Type: Text/Plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Message-Id: <201303131812.36388.Mark.Martinec+freebsd@ijs.si> X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 13 Mar 2013 17:13:20 -0000 Schrodinger wrote: > What I am confused about is that without ACCEPT_RTADV on re0, FreeBSD > doesn't perform Neighbour Solicitation for the default gateway but with > ACCEPT_RTADV it does ..... Why ? This is Neighbour Solicitation and not > Router Solicitation.... > > I understand that FreeBSD doesn't consider the defaulte gateway to be > "on-link" so it does not perform ND for it but why does it perform ND > when ACCEPT_RTADV is set on re0 ? "Surely" ACCEPT_RTADV only affects > Router Advertisements / Solicitations and not ND. > > I have done packet captures and with ACCEPT_RTADV I see the initial > Neighbour Solicitation and the Neighbour Advertisement to and from my > default gateway. > > Without ACCEPT_RTADV - FreeBSD simply doesn't try to perform ND for the > address. This is where I am uncertain if this is expected or not. That is a good question and I'd be interested in an answer too. Perhaps FreeBSD is implementing a predecessor to RFC 4861, i.e. the now obsolete RFC 2461: RFC 4861, Appendix F: Changes from RFC 2461 o Removed the on-link assumption in Section 5.2 based on RFC 4943, "IPv6 Neighbor Discovery On-Link Assumption Considered Harmful". RFC 4943, Abstract This document describes the historical and background information behind the removal of the "on-link assumption" from the conceptual host sending algorithm defined in Neighbor Discovery for IP Version 6 (IPv6). According to the algorithm as originally described, when a host's default router list is empty, the host assumes that all destinations are on-link. Mark