Well-known manufacturers of network adapters put a sequence of digits in the MAC address that identifies them as the manufacturer. It is called Organizationally Unique Identifier (OUI).
How the MAC Address Works
The attribute consists of a string of characters identifying the network device. The address is linked to a network interface card (NIC), which is a computer board that connects the computer to the network. The NIC converts data into an electrical signal transmitted over the network.
Any network card receives a unique MAC address during manufacture. While IP addresses are associated with TCP/IP network software, MAC addresses are associated with network adapter hardware.
What the MAC Address is used for?
All devices on the same subnet have different MAC addresses. Unlike dynamic IP addresses, they are static, which is useful for diagnosing network problems. For a network administrator, a MAC address is a reliable way to identify network data senders and receivers.
In wireless networks, MAC address filtering prevents unwanted network access. When filtering, the router is configured to receive traffic only from certain MAC addresses. Devices with approved MAC addresses can communicate over the network even if they have been assigned a new IP address. A hacker who has captured the IP address of the network will be blocked because their MAC address is not included in the approved list.