On Wed, 2009-02-25 at 10:20 +0100, Henning Rogge wrote:
> Am Wednesday 25 February 2009 10:16:06 schrieb Outback Dingo:
[....]
> > it really shouldnt matter what brand the router is, as Ive never seen MAC
> > duplication by vendors. Has anyone ?? Someone flip me a

First, you won't notice such a clash in the cabled world unless it
happens these 2 identical MAC addresses happen to be in the same
broadcast domain.
So IMHO chances are quite small (read: IMHO next to zero) for this to
happen.
Second if you look for a counter example: Solaris 2.5/SunOS-5.5 (sorry,
I hadn't access to more recent versions) generates the MAC addresses for
*all* interfaces out of it's hostid (which has 4 bytes and is supposed
unique within all Sun hardware according to Sun).
And that works in almost all cases without any problems because there
are very few occasions where one connects one host with more than one
ethernet to the same IP net[0].

> > working configuration to look at.
> If a vendor would produce a colliding MAC he is doing something wrong.

And in which way does that help if one encounters exactly that problem
in the field?

And BTW: One could simply change the MAC address at boot time of a
device - with good or not so good intentions.

	Bernd

[0]: One is: Solaris had a hardcoded limit on how many IP addresses you
     can configure on one ethernet card. Before HTTP-1.1 times, it was
     common to give each virtual host a separate IP address. And now
     imagine large hosters with *lots* of virtual hosts on a few (big)
     servers. The simplest solution was: add a second network card to
     double the possible IP addresses on that host (and explicitly
     configure a different MAC address to not confuse the switch).
-- 
Firmix Software GmbH                   http://www.firmix.at/
mobil: +43 664 4416156                 fax: +43 1 7890849-55
          Embedded Linux Development and Services




