MAC, Media Access Control, address is a globally unique identifier assigned to network devices, and therefore it is often referred to as hardware or physical address. MAC addresses are 6-byte (48-bits) in length, and are written in MM:MM:MM:SS:SS:SS format. The first 3-bytes are the ID number of the manufacturer, which is assigned by an Internet standards body. The second 3-bytes are serial numbers assigned by the manufacturer.

address and the host address. A subnet mask separates the IP address into the network and host addresses (<network><host>). Subnetting further divides the host part of an IP address into a subnet and host address (<network><subnet><host>) if additional subnetwork is needed. Use the Subnet Calculator to retrieve subnetwork information from the IP address and Subnet Mask. It is called a subnet mask because it is used to identify the network address of an IP address by performing a bitwise AND operation on the netmask.