From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marc Haber Subject: Re: Bridge stays down until a port is added Date: Sun, 21 Aug 2011 14:13:05 +0200 Message-ID: <20110821121305.GA22232@torres.zugschlus.de> References: <20110811070659.GA21307@torres.zugschlus.de> <20110811081706.7307e8b2@nehalam.ftrdhcpuser.net> <20110811205429.GB21307@torres.zugschlus.de> <20110820094712.GC21307@torres.zugschlus.de> <20110820093059.75c37a1f@nehalam.ftrdhcpuser.net> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Cc: netdev@vger.kernel.org, Sven-Haegar Koch To: Stephen Hemminger Return-path: Received: from torres.zugschlus.de ([85.214.131.164]:45650 "EHLO torres.zugschlus.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754197Ab1HUMNI (ORCPT ); Sun, 21 Aug 2011 08:13:08 -0400 Content-Disposition: inline In-Reply-To: <20110820093059.75c37a1f@nehalam.ftrdhcpuser.net> Sender: netdev-owner@vger.kernel.org List-ID: On Sat, Aug 20, 2011 at 09:30:59AM -0700, Stephen Hemminger wrote: > The problem is that IPv6 Duplicate Address Detection needs to > work. This is not a simple problem. If the bridge asserted > carrier with no ports then: > > 1. IPv6 address assigned and IPv6 decides it is okay. > 2. Port added later > 3. Another system has the same address. > *broke* Same situation when a system-to-system-link is added after bringing up an interface. I agree that the issue is not an issue if a real switch is being used. > If you want to avoid DAD, then you can configure disable DAD > by setting /proc/sys/net/ipv6/conf/br0/accept_dad to 0 I'd like to avoid that. 2001:db8::1 Would it acceptable (and clean!) to have: eth0: 2001:db8:1::100/64 default gw to the internet is 2001:db8:1::1 lo: 127.0.0.1/8, ::1/128, 2001:db8:2::100/64 br0: 2001:db8:2::1/64 (being default gw for the VMs connected to br0, routing 2001:db8:2::/64 to the Internet) Note 2001:db8:2::/64 being used both on lo and br0, with 2001:db8:2::100 meant to be reachable from the Internet even if no VM is already up. my hostname will be A-Recorded to 2001:db8:2::100 with proper reverse DNS. The background for doing so is that I cannot control the reverse DNS for the IP addresses inside 200a:db8:1::/64 in a lot of my setups (for example, if my IPv6 comes in via Sixxs). Is this going to work in a clean way? Greetings Marc -- ----------------------------------------------------------------------------- Marc Haber | "I don't trust Computers. They | Mailadresse im Header Mannheim, Germany | lose things." Winona Ryder | Fon: *49 621 72739834 Nordisch by Nature | How to make an American Quilt | Fax: *49 3221 2323190