From MEPIS Documentation Wiki
A mac address is a unique identifier attached to network adapters. It is often useful to determine the mac address when resolving problems.
To find out the mac address of a particular adapter, open a terminal and type:
The first line of the return shows the mac address after "HWaddr", for example:
eth 0 Link encap:Ethernet HWaddr 00:07:E9:4D:B6:40