Sticky learning and variable MAC address on Win XP
 

Hi Foks,
I've been Googling for this but not found anything that helps. On
one of our networks we use Catalysts with sticky learning to limit the
changes of MAC addresses that can occur - we get the first one and then
require intervention when it needs to be changed. It's a halfway house
to registering and configuring all MAC addresses.

It appears that WinXP does strange things on startup, probably setting
the locally administered bit in the MAC address initially before
settling down with the burnt in address. Obviously this causes
problems with the sticky learning because the Catalyst port shuts
itself down when the MAC address changes to the properly registered
one. Does anyone know why this happens and if anything can be done
about it?

Thanks,

Sam Wilson
Infrastructure Services Division
Computing Services, The University of Edinburgh
Edinburgh, Scotland, UK