ARP

ARP is a communication protocol used for discovering the link layer address, such as a MAC address, associated with a given internet layer address, typically an IPv4 address. This mapping is a critical function in the Internet protocol suite. ARP was defined in 1982 by RFC 826 which is Internet Standard STD 37.

In Internet Protocol Version 6 (IPv6) networks, the functionality of ARP is provided by the Neighbor Discovery Protocol (NDP).

To manipulate or display ARP table entries, the following commands are implemented.

Configure

set protocols static arp 192.0.2.100 hwaddr 00:53:27:de:23:aa

This will configure a static ARP entry always resolving 192.0.2.100 to 00:53:27:de:23:aa

Operation

show protocols static arp

Display all known ARP table entries spanning accross all interfaces

vyos@vyos:~$ show protocols static arp
Address                  HWtype  HWaddress           Flags Mask     Iface
10.1.1.1                 ether   00:53:00:de:23:2e   C              eth1
10.1.1.100               ether   00:53:00:de:23:aa   CM             eth1
show protocols static arp interface eth1

Display all known ARP table entries on a given interface only (eth1):

vyos@vyos:~$ show protocols static arp interface eth1
Address                  HWtype  HWaddress           Flags Mask     Iface
10.1.1.1                 ether   00:53:00:de:23:2e   C              eth1
10.1.1.100               ether   00:53:00:de:23:aa   CM             eth1