Sorry - I missed the original post - but I can think of one scenario where two NICs have the same MAC address. However, it's extremely unusua.l. The IEEE has managed the allocation of addresses for Ethernet, but IBM has done the same for Token Ring. The two didn't talk, and so their allocated address ranges overlap. Consequently there are a number of pairs of Token Ring and Ethernet cards out there that have the same MAC address. Token Ring/Ethernet bridges have to do some bit-fiddling to map TR MAC's to Ethernet because of it. That's probably not what the OP was enquiring about - unless he's extremely unfortunate and still has to deal with TR. Best, --- Les Bell, RHCE, CISSP [http://www.lesbell.com.au] Tel: +61 2 9451 1144 FreeWorldDialup: 800909