The arp command enables the creation, editing, and display of mappings of physical addresses to known IPv4 addresses. The arp command is executed from the Windows command prompt.

To execute an arp command, at the command prompt of a host, enter:

C:\host1> arp -a

As shown in the figure the arp –a command lists all devices currently in the ARP cache of the host, which includes the IPv4 address, physical address, and the type of addressing (static/dynamic), for each device.

The cache can be cleared by using the arp -d command in the event the network administrator wants to repopulate the cache with updated information.

Note: The ARP cache only contains information from devices that have been recently accessed. To ensure that the ARP cache is populated, ping a device so that it will have an entry in the ARP table.