For those of you who have heard of Address Resolution Protocol (ARP) and think that Reverse Address Resolution Protocol (RARP) is its complement, they are totally off track. RARP is a computer networking protocol used by a host computer to request for an IPV4 address from another host computer if it does not have one used (not statically assigned), the Network Interface that is connected to the network would already have a Layer 2 MAC address (hardware address).
This might very well sound like DHCP which is very popular and does the same thing. In fact RARP has been rendered obsolete by two of its successors, the Bootstrap Protocol (BOOTP) and the newer Dynamic Host Configuration Protocol (DHCP), which have better features than RARP.
In an RARP setup, one or more server hosts maintain a database of mappings of Link Layer addresses to their respective protocol addresses (similar to an IP to MAC mapping in Ethernet networks). Media Access Control (MAC) addresses needed to be individually configured on the servers by an administrator (this is where DHCP rules and RARP got kicked out). RARP was limited to serving only IP addresses.
Another misnomer is that Reverse ARP is the same as Inverse Address Resolution Protocol (InARP). But InARP was designed to get the IP address associated with another host’s MAC address. InARP is actually just the reverse of ARP in functionality.
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