Reverse Address Resolution Protocol (RARP) associates a known MAC addresses with an IP addresses.
A network device, such as a diskless workstation, might know its MAC address but not its IP address.
RARP allows the device to make a request to learn its IP address.
Devices using RARP require that a RARP server be present on the network to answer RARP requests.
The source device must include both its MAC address and IP address in order for the destination device to retrieve data