Mac OS X Server 10.x
1. Open the Apple System Profiler application found at /Applications/Utilities.
2. Look in the Network Overview of the System Profile to find your Mac Address.
On Mac OS X Server 1.x,
1. Open the Terminal application.
2. Type: netstat -I en0
Note: This assumes en0 is the Ethernet interface.
3. Press Return
The hardware Ethernet address is located in the Address column of the output.
If the computer is connected to a NetInfo network using broadcast binding, the hardware address and owner of the machine can be determined by typing the following command:
nidump -r /machines .. > machines.txt
The file machines.txt may then be searched for a person's name, IP address, or hardware Ethernet address.