rarp

rarp [-v] [-t ] -a
rarp [-v] [-t ] -d hwaddr
rarp [-v] [-t ] -s hwaddr

-a
    Display all of the entries in the RARP table.

-d hwaddr
    Delete the RARP entry for the given with the hardware address hwaddr. Requires root privileges.

-s hwaddr
    Create a RARP entry for the given with the hardware address hwaddr. Requires root privileges.

-t
    Specify the hardware address type. The default is ether (Ethernet). Other possible values include ax25, pronet, chaos, ieee802, arcnet, appletalk, dlci, atm, metricom.

-v
    Be verbose. Print more information during execution.

The rarp command is used to manipulate the kernel's Reverse Address Resolution Protocol (RARP) table. RARP is a protocol that allows a machine to discover its IP address by broadcasting its MAC address to a RARP server, which then replies with the machine's IP address. This is useful for diskless workstations or machines that don't have a persistent storage device to store their IP address. The rarp command is primarily used to add, delete, or list entries in the kernel's RARP table. Adding an entry maps a hardware (MAC) address to an IP address, allowing the system to respond to RARP requests for that hardware address. Deleting an entry removes the mapping. Listing the entries allows you to view the current mappings in the RARP table. Note that RARP is an older protocol and is largely superseded by BOOTP and DHCP, which provide more sophisticated configuration capabilities. The utility may require root privileges to execute successfully, especially when adding or deleting table entries.

The command output might vary depending on the Linux distribution and available network configuration tools.

RARP is largely obsolete and superseded by BOOTP and DHCP. Support may be limited or absent in modern systems. Requires root privileges to add or delete entries.

rarp -a: Displays the current RARP table.
rarp -s myhost 00:11:22:33:44:55: Creates a RARP entry for myhost with the specified hardware address. Requires root privileges.
rarp -d myhost 00:11:22:33:44:55: Deletes the RARP entry for myhost. Requires root privileges.

RARP was developed in the early 1980s as a mechanism for diskless workstations to determine their IP addresses. The command line utility rarp was created to facilitate the administration of RARP tables, enabling system administrators to manually configure the mapping between hardware addresses and IP addresses. As BOOTP and then DHCP emerged, providing more dynamic and comprehensive network configuration capabilities, the use of RARP declined significantly.

arp(8), ifconfig(8), route(8), ip(8), dhcpd(8)