What is an Ethernet MAC address?
Since many machines may share a single Ethernet wire, each must have an individual identifier. This doesn’t happen with dial-up modems, because it is assumed that any data you send to the modem is destinated for the other side of the phone line. But when you send data out onto an Ethernet wire, you have to be clear which machine you intend to send the data to. Sure, in many cases today there are only two machines talking to each other, but you have to remember that Ethernet was designed for thousands of machines to share the same wire. This is accomplished by putting a unique 12-digit hex number in every piece of Ethernet hardware. Section 1.5.4 explains how to discover the Ethernet MAC address of your own machine. To really understand why this is so important, you might want to review the information in section 5.4 below. Ethernet was designed to carry other traffic than just TCP/IP, and TCP/IP was designed to run over other wires (such as dial-up lines, which use no Ethernet). For ex
