What type of address is used to uniquely identify a device on a local network?

The MAC address is fundamentally designed to uniquely identify a device on a local network. Each network interface card (NIC) has a built-in MAC address, which is a hardware address that is used in the data link layer of the OSI model. This address is usually represented in a hexadecimal format and is hard-coded into the hardware, making it a reliable way to distinguish one device from another within the same local area network (LAN).

Public and private IP addresses serve different purposes. A public IP address is used to identify devices on the internet, whereas a private IP address is used within private networks and can be shared among multiple devices on a local network. While both types of IP addresses are essential for network communication, they do not uniquely identify devices in the same manner as MAC addresses do at the link layer.

Domain names are a human-readable way to identify devices, mapped from IP addresses for easier access, but they do not serve as unique identifiers at the hardware level on a local network. Thus, in the context of identifying devices on a local network, the MAC address is the correct and most appropriate choice.