Which address is assigned to a network interface to uniquely identify it on a local network?

• A. MAC address
• B. IP address
• C. Hostname
• D. DNS name

Answer: (A)

The main idea is hardware addressing on a local network. A MAC address is a unique identifier assigned to a network interface by the manufacturer and is used to identify that specific NIC on the local link. On a LAN, data frames carry the destination and source MAC addresses, so the hardware address is what ensures frames reach the right device at the data-link layer.

IP addresses, on the other hand, are logical addresses for routing between networks and can change as devices connect to different networks or obtain new configurations. Hostnames and DNS names are human-readable labels that map to IP addresses, not the low-level identifier used for local frame delivery.

So, the address that uniquely identifies a network interface on a local network is the MAC address.