SANS Institute - arp

=Description=
The Address Resolution Protocol (ARP) is a protocol for mapping an Internet Protocol address (IP address) to a computer hardware address (MAC address). ARP is used by devices on a local area network (LAN) to resolve the MAC address of another device on the network. It is also used by a host to check whether an IP address is already in use.

ARP was defined in 1982 by RFC 826, which was superseded by RFC 903 in 1984.=More Information=
https://en.wikipedia.org/wiki/Address_Resolution_Protocol