IP Aliasing

In a LAN environment, clients and servers are connected to the network by one or more network controller cards. Each controller has a factory-set (hard-coded) primary physical address called the MAC address. The MAC address is also known as the primary unicast address. For an Ethernet controller, the MAC address is a string of hex bytes that looks, for example, like this: 08:0a:10:bc:7f:5d

In addition to its own name, the controller can recognize up to 16 alias names placed in the its drivers multicast address list. The controller accepts any packet sent to its primary unicast address and any packets sent to an address in its multicast list.