From mboxrd@z Thu Jan 1 00:00:00 1970 From: Inaky Perez-Gonzalez Subject: Re: What makes a good fake MAC address? Date: Wed, 22 Apr 2009 15:38:10 -0700 Message-ID: <200904221538.10964.inaky@linux.intel.com> References: <20090423070442.1e643b5b.ipng@69706e6720323030352d30312d31340a.nosense.org> <200904221515.05459.inaky@linux.intel.com> <20090422152539.7a7e073a@s6510> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Cc: Mark Smith , netdev@vger.kernel.org To: Stephen Hemminger Return-path: Received: from mga07.intel.com ([143.182.124.22]:10862 "EHLO azsmga101.ch.intel.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750825AbZDVWiL (ORCPT ); Wed, 22 Apr 2009 18:38:11 -0400 In-Reply-To: <20090422152539.7a7e073a@s6510> Content-Disposition: inline Sender: netdev-owner@vger.kernel.org List-ID: On Wednesday 22 April 2009, Stephen Hemminger wrote: > On Wed, 22 Apr 2009 15:15:05 -0700 > > Inaky Perez-Gonzalez wrote: > > On Wednesday 22 April 2009, Mark Smith wrote: > > > Hi Inaky, > > > > > > (please CC me, I'm not on the list) > > > > > > "The problem with using a zero mac address is that it confuses the > > > bridging software (and maybe others). I was wondering, what would > > > be a fake mac address we could put in there that is legal for this > > > kind of "faking"? [or the closest thing to legal?]" > > > > > > Since you're from an organisation with an OUI allocation or two, I > > > think a real Intel one would be best. It then wouldn't be fake, and > > > no matter where it was exposed (host only, local network, or > > > globally e.g. in IPv6 node addresses), it would be guaranteed not > > > to collide with any other addresses (unless Intel make error an > > > error in their own OUI administration.) > > > > It doesn't really work, because it is for the "from" end of the > > connection; as said somewhere else in the thread, the WiMAX link is > > P2P, IP only. The card has a local address, that we use for the "to" > > field, but for the from, we need to fake an address from the network > > -- which is not necessarily an intel device :) > > > > So maybe local addresses would not be the right choice, and clearly > > Intel assigned ones neither :) > > You need a from address for the bridge to be able to populate its > forwarding table. If remote end is always same, just get some random > address at start of tunnel and reuse it. Nope, the remote end will change as you move around from base station to base station :( -- Inaky