Reverse Address Resolution Protocol

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Reverse Address Resolution Protocol (RARP) is a network layer protocol used to obtain an IP address for a given hardware address (such as an Ethernet address). RARP is described in the IETF's RFC 903. It has been rendered obsolete by Bootstrap Protocol and the more modern Dynamic Host Configuration Protocol, which both support a much greater feature set than RARP.

The primary limitations of RARP are that each MAC address must be manually configured on a central server, and that the protocol only conveys an IP address. This leaves configuration of subnetting, gateways, and other information to other protocols or the user. Another limitation of RARP compared to BOOTP or DHCP is that it is a non-IP protocol. This means that like ARP it cannot be handled by the TCP/IP stack on the client, but is instead implemented separately.

Reverse ARP is the complement of the Address Resolution Protocol. RARP also differs from Inverse Address Resolution Protocol (InARP), which is designed to locate the IP address associated with another station's MAC address.