Dell server responding with two mac addresses

[Fredrik Carlsson]

Hi,

I have a rather serious problem, I have three dell server (PE1800, 
PE2950 and SC1425) the PE1800 is running FreeBSD 6.1. The problem that I 
have is that the PE1800 is responding with two mac adresses on the same 
network interface, has anywone seen this before? This causes our router 
to be confused on where to send the traffic so one of the other machines 
can't access anything outside our router. The first thought was that 
dells IPMI-interface would have something to do with it but after 
disabling IPMI on all machines the problem is still there.

Any help is appreciated.

Best regards
Fredrik Carlsson