MAC addresses are used as a network address and is oftern referred as a hardware physical address.

Usually MAC address are printed on the back fn the devices and are 6-byte (48-bits) in length, and are written in MM:MM:MM:SS:SS:SS format. The first 3-bytes are ID number of the manufacturer, which is assigned
by an Internet standards body. The second 3-bytes are serial number assigned by the manufacturer.

You can also find your MAC addresses on a Windows based computer by accessing the command prompt and typing:

"ipconfig /all" where all the adapters are listed with the associated MAC address.

In Unix,Linux,Apple and other similar operating systems the rerminal command "ifconfig" displays all adapters with the associated hardware and other information.