What is MAC Address?

A MAC (Media Access Control) address is a unique identifier assigned to network interfaces for communications on the physical network segment. MAC addresses are used as a network address for most IEEE 802 network technologies, including Ethernet and WiFi. They are used to identify the devices on a network and are usually represented in a hexadecimal format, such as 00:11:22:33:44:55. 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 ID number of the manufacturer, which is assigned by an Internet standards body. The second 3-bytes are serial number assigned by the manufacturer.

Each device on a network has its own unique MAC address, which is usually assigned by the manufacturer of the device. MAC addresses are used for various purposes, including identifying devices on a network and allowing them to communicate with each other. In some cases, MAC addresses can also be used to track the location of a device on a network.

MAC layer represents layer 2 of the TCP/IP (adopted from OSI Reference Model), where IP represents layer 3. MAC address can be thought of as supporting hardware implementation whereas IP address supports software implementation. MAC addresses are permanently burned into hardware by hardware manufacturer, but IP addresses are assigned to the network devices by a network adminstrator. DHCP relies on MAC address to assign IP addresses to network devices.

How do I find a MAC address of network device?

Operating Systems support various command-line and GUI utilities to allow users to find MAC address of the system.
On Unix variants including Solaris and Linux support “ifconfig -a”, “ip link list” or “ip address show” command that displays MAC address of the network device among other useful information.
On Windows “ipconfig /all” command that displays MAC address.
On a MacOS, one can find MAC address by opening “System Preferences”, then selecting “Network”.