nanog mailing list archives

Re: The tale of a single MAC


From: Graham Wooden <graham () g-rock net>
Date: Sat, 01 Jan 2011 22:47:38 -0600

Two different suppliers - one was out of Wisconsin (I believe; it's been
some time), and the other of Phoenix for the most recent batch.

I have lots and lots of HP server gear - and never encountered such bizarre
issue.


On 1/1/11 9:59 PM, "Brielle Bruns" <bruns () 2mbit com> wrote:

On 1/1/11 8:33 PM, Graham Wooden wrote:
So ­ here is the interesting part... Both servers are HP Proliant DL380 G4s,
and both of their NIC1 and NIC2 MACs addresses are exactly the same.  Not
spoofd and the OS drivers are not mucking with them ... They¹re burned-in ­
I triple checked them in their respective BIOS screen.  I acquired these two
machines at different times and both were from the grey market.  The ³What
the ...² is sitting fresh in my mind ...  How can this be?


 From the same grey market supplier?

I know HP has a disc they put out which updates all the firmware/bios in
a specific server model, its not too far fetched that a vendor might
have a modified version that also either purposely or accidentally
changes the MAC address.  Off the top of my head, I'm not sure where the
MAC is stored - maybe an eeprom or a portion of the bios flash.  Or, it
could be botched flashing that blew away the portion of memory where
that was stored and the system defaulted to a built in value.

Excellent example is, IIRC, the older sparc stuff, where the ethernet
cards didn't have MAC addresses as part of the card, but were stored in
non-volatile or battery backed memory.  Memory goes poof, and you'll
have problems.  Some WRT54G/WAP54Gs suffer from the same problem when
throwing third party firmware on there.




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