[Fwd:] Nvidia NICs with duplicate mac addresses

Robert D. Scott robert at ufl.edu
Fri Sep 5 10:01:53 CDT 2008

Does this MAC present itself all the time, or just during boot?

Marvel makes a NIC prevalent in some Dell systems, that presents MAC
0c00.0000.0000 during its startup process. If you run port security, and
several people boot their computer within the cam table expiration period,
port security will disable the port. You can work around it but it is time
consuming in large networks where port security are enabled.

Robert D. Scott                 Robert at ufl.edu
Senior Network Engineer         352-273-0113 Phone
CNS - Network Services          352-392-2061 CNS Receptionist
University of Florida           352-392-9440 FAX
Florida Lambda Rail             352-294-3571 FLR NOC
Gainesville, FL  32611          321-663-0421 Cell

-----Original Message-----
From: Robert E. Seastrom [mailto:rs at seastrom.com] 
Sent: Friday, September 05, 2008 10:33 AM
To: nanog at nanog.org
Subject: [Fwd:] Nvidia NICs with duplicate mac addresses

Forwarded to NANOG in the interests of wider awareness...  having been
there and torn out my already scarce hair, duplicate MAC addresses can
really mess up your day...


Just when you thought this couldn't happen any more...

Copying from a different email list...

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:

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.

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