RARP stands for Reverse ARP. RARP is the opposite of ARP. ARP is used when the IP address is known but the physical address is not known. RARP is used when the physical address is known but the IP address is not known. RARP is often used in conjunction with the BOOTP protocol to boot diskless workstations.
BOOTP (boot PROM)— Many network adapters contain an empty socket for insertion of an integrated circuit known as a boot PROM. The boot PROM firmware starts as soon as the computer is powered on. It loads an operating system into the computer by reading it from a network server instead of a local disk drive. The operating system downloaded to the BOOTP device is pre-configured for a specific IP address.