[Fwd:] Nvidia NICs with duplicate mac addresses

Kevin Oberman oberman at es.net
Fri Sep 5 10:02:27 CDT 2008

> Date: Fri, 5 Sep 2008 10:36:24 -0400
> From: "Jay R. Ashworth" <jra at baylink.com>
> On Fri, Sep 05, 2008 at 10:32:46AM -0400, Robert E. Seastrom wrote:
> > mac address 04:4b:80:80:80:03, was showing up in multiple places  
> > across the network. I googled the mac address and discovered that  
> > other people are having the same issue with this mac address. Below  
> > are some links describing the problem:
> > 	
> > http://forums.nvidia.com/index.php?showtopic=22148
> > http://www.nvnews.net/vbulletin/archive/index.php/t-73469.html
> > 
> > I just wanted everyone to know about this problem in case you run  
> > across similar slow "connectivity" issues. I believe the network card  
> > is made by NVIDIA.
> FWIW, IEEE's OUI lookup page says that's not assigned to *anyone*.
> 	http://standards.ieee.org/regauth/oui/index.shtml

No, the IEEE page does not say anything. For many years IEEE considered
OUIs to be confidential by default. IEEE would list the OUI only if a
box was checked on the application for the OUI. At some point the
default was changes to make the OUIs public, but existing "private"
entries remain private.

That said, it turns out the nVidia's OUI is 00:04:4B. So it looks like
the addressing was completely hosed and the MAC was shifted over 1 byte.

What  mess! This used to happen in the early days of Ethernet, but I
have not seen it in some time.
R. Kevin Oberman, Network Engineer
Energy Sciences Network (ESnet)
Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab)
E-mail: oberman at es.net			Phone: +1 510 486-8634
Key fingerprint:059B 2DDF 031C 9BA3 14A4  EADA 927D EBB3 987B 3751
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