From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754021AbYE1Kee (ORCPT ); Wed, 28 May 2008 06:34:34 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752051AbYE1KeX (ORCPT ); Wed, 28 May 2008 06:34:23 -0400 Received: from smtp-dmz-233-wednesday.dmz.nerim.net ([195.5.254.233]:55007 "EHLO kellthuzad.dmz.nerim.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751414AbYE1KeW (ORCPT ); Wed, 28 May 2008 06:34:22 -0400 X-Greylist: delayed 1978 seconds by postgrey-1.27 at vger.kernel.org; Wed, 28 May 2008 06:34:22 EDT Message-ID: <483D2D11.9080803@plouf.fr.eu.org> Date: Wed, 28 May 2008 11:59:45 +0200 From: Pascal Hambourg Organization: Plouf ! User-Agent: Mozilla Thunderbird 1.0.6 (Windows/20050716) X-Accept-Language: fr,en MIME-Version: 1.0 To: Willy Tarreau CC: Matthias Cramer , James Chapman , Andrew Morton , linux-kernel , netdev@vger.kernel.org Subject: Re: Wired behaviour with IPv6 over PPP References: <48341C0B.7010003@interway.ch> <20080522014959.0f6191aa.akpm@linux-foundation.org> <48354318.60202@katalix.com> <4835C40B.60603@interway.ch> <20080524042911.GE6749@1wt.eu> In-Reply-To: <20080524042911.GE6749@1wt.eu> Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello all, Willy Tarreau a écrit/wrote : > On Thu, May 22, 2008 at 09:05:47PM +0200, Matthias Cramer wrote: > >>James Chapman wrote: >> >>>Andrew Morton wrote: >>> >>>>On Wed, 21 May 2008 14:56:43 +0200 Matthias Cramer >>>> wrote: >>>> >>>>>I have a very wired behaviour when doing IPv6 over PPPoE. >>>>> >>>>>The situation: >>>>> >>>>>A linux box connected to a DSL Modem, on the other side is a Cisco >>>>>LNS which terminates the PPP session (actually L2TP). >>>>>I have control over both ends. >>>>> >>>>>When I have net.ipv6.conf.all.forwarding set to 0 then the ppp >>>>>Interface gets a IPv6 address from the Cisco via IP6CP. >>>>>When I have net.ipv6.conf.all.forwarding set to 1 them the ppp >>>>>Interface does not get an address, it has only a normal link local >>>>>address. AFAIK IPV6CP/PPP only allows to negotiate link local addresses. So I guess the global address and default route is assigned by another mechanism, maybe stateless autoconfiguration using router advertisement, although I was not aware it could be used on a PPP link because of the absence of MAC address. Enabling global forwarding (net.ipv6.conf.all.forwarding=1) disables stateless autoconfiguration (see ip-sysctl.txt in kernel documentation) on all interfaces. I believe this is consistent with the observed behaviour. >>>>>When I start the ppp session with forwarding set to 0 I can ping out >>>>>and there exists a default route to ppp0 , then I switch forwarding to 1 >>>>>the default route disappears and therefore routing does not work any >>>>>longer. I have read reports about this. I guess the logic is that enabling forwarding turns the box into a router, so the default route learned from another router's advertisements by autoconfiguration should be deleted. Even the autoconfigured global address will eventually expire. > Well, at least it has been working for years in kernel 2.4 for me with > pppd 2.4.2b3 to 2.4.4 (I've not upgraded my firewall to 2.6 yet). So > it has definitely been working at some point. What exactly has been working ? PS : Willy, do you plan to backport the security fix for the sit module from 2.6.25.3 into 2.4 ?