Address Resolution Protocol (ARP) is a protocol used for finding MAC address associated with IPv4 address. This protocol work as an interface between the OSI network and OSI Data link layer. Address Resolution Protocol (ARP) is a protocol used to map an IP address to a recognized physical machine address on the LAN. When the incoming packet sent to a host machine on a given local network reaches a gateway, the gateway instructs the ARP program to locate a MAC address or a physical host which matches the IP address. The ARP program searches the ARP cache and, if the address is found, gives it so that the packet will be converted to the appropriate format and length and sent to the machine. If no IP address input is found, ARP will release a special format request packet to every machine on the LAN to identify whether a machine knows it has that associated IP address.