(ARP) A process in Internet Protocol (IP) networks that allows a host to find the Media Access Control (MAC) address of a target host on the same physical network when it only knows the target's IP address.
With ARP, a network board contains a table that maps IP addresses to the hardware addresses of the objects on the network.
To create entries, the ARP broadcasts a request with the target's IP address. The target responds with its physical address. The network board adds the physical address to its ARP table and can then send packets to the target.