Which protocol is used to determine the IP address that corresponds to a MAC address?

The protocol used to determine the IP address that corresponds to a MAC address is ARP (Address Resolution Protocol). ARP functions at the link layer of the OSI model and is primarily used in IPv4 networks. When a device knows the MAC address of another device but needs to find its corresponding IP address, it sends out an ARP request on the network. This request asks "Who has IP address X.X.X.X? Tell me your MAC address." The device with the matching IP address responds with its MAC address, allowing the requesting device to establish a direct link for communication.

Understanding the purpose of ARP is essential because it facilitates the process of mapping logical addresses (IP addresses) to physical addresses (MAC addresses) in a local network environment, which is crucial for computer networking operations. This is particularly important in scenarios where devices need to communicate within the same local area network without needing to know the routes or broader network structure.