The Reverse Address Resolution Protocol (RARP) is a protocol used to map a known MAC address to an IP address. RARP is used by a computer to request its IP address from a gateway server's Address Resolution Protocol (ARP) table or cache. This protocol is now largely obsolete and has been replaced by more modern protocols like BOOTP and DHCP.
| Hardware Type (16 bits) | Protocol Type (16 bits) | ||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Hardware Length (8 bits) | Protocol Length (8 bits) | Operation (16 bits) | |||||||||||||||||||||||||||||||||||||||||||||
| Sender Hardware Address (48 bits) | |||||||||||||||||||||||||||||||||||||||||||||||
| Sender Protocol Address (32 bits) | |||||||||||||||||||||||||||||||||||||||||||||||
| Target Hardware Address (48 bits) | |||||||||||||||||||||||||||||||||||||||||||||||
| Target Protocol Address (32 bits) | |||||||||||||||||||||||||||||||||||||||||||||||
Specifies the network protocol type. For Ethernet, this is 1. Back to header
Specifies the internetwork protocol for which the RARP request is intended. For IPv4, this is 0x0800. Back to header
Length in bytes of a hardware address. For Ethernet, this is 6. Back to header
Length in bytes of a protocol address. For IPv4, this is 4. Back to header
Specifies the operation being performed: 3 for request, 4 for reply. Back to header
The hardware address of the sender. Back to header
The protocol address of the sender. Back to header
The hardware address of the intended receiver. Back to header
The protocol address of the intended receiver. Back to header