Command Reference

show ip arp

Address Resolution Protocol (ARP) establishes correspondences between network-layer addresses (Layer 3) and LAN hardware addresses (Layer 2 Media Access Control [MAC] address). A record of each correspondence is kept in a cache on the router for a predetermined amount of time and then discarded. Viewing the ARP cache can sometimes be a quick way to view or verify directly connected hosts to the router.
show ip arp
Example
Router# show ip arp

  Protocol  Address       Age(min)Hardware Addr  Type Interface
Internet  171.69.233.22 9       0000.0c59.f892 ARPA Ethernet0/0
Internet  171.69.233.21 8       0000.0c07.ac00 ARPA Ethernet0/0
Each field of the output is described below:

Field Value Description

Protocol Internet Protocol for network address in the Address field.

Address 171.69.233.22 The network address that corresponds to hardware address.

Age (min) 9 Age, in minutes, of the cache entry; a hyphen (-) means the address is local

Hardware Addr 0000.0c59.f892 Data-link address

Type ARPA Type of encapsulation:

ARPA—Ethernet

SNAP—RFC 1042

SAP—IEEE 802.3

Interface Ethernet0/0 Interface to which this address mapping has been assigned

Use the clear arp-cache command to clear the IP ARP cache.

Field	Value	Description
Protocol	Internet	Protocol for network address in the Address field.
Address	171.69.233.22	The network address that corresponds to hardware address.
Age (min)	9	Age, in minutes, of the cache entry; a hyphen (-) means the address is local
Hardware Addr	0000.0c59.f892	Data-link address
Type	ARPA	Type of encapsulation: ARPA—Ethernet SNAP—RFC 1042 SAP—IEEE 802.3
Interface	Ethernet0/0	Interface to which this address mapping has been assigned