Address Resolution Protocol (ARP) display and control


arp [-n] hostname
arp [-nv] -a
arp [-v] -d -a
arp [-v] -d hostname [pro [iface_name]]
arp -s hostname ether_addr [temp] [pub [pro [iface_name]]]
arp -f filename

Runs on:



Display all of the current ARP entries.
-d hostname
Delete an entry for the specified host. Only the superuser can use this option.
-f filename
Load the ARP cache with entries found in the specified file. Entries in the file should be of the form:
hostname ether_addr [pub] [temp]

with argument meanings as given for the -s option.

Don't try to resolve hostnames.
-s hostname ether_addr [temp] [pub [pro [iface_name]]]
Create an ARP entry for the host hostname with the Ethernet address ether_addr. The Ethernet address is given as six hex bytes separated by colons.

If pub is given, the entry is "published." That is, this system acts as an ARP server, responding to requests for hostname, even though the IP address that's mapped to hostname isn't the address of this system.

The entry is permanent unless the word temp is given in the command.

Specify the pro string to create or delete a proxy-only ARP entry.

The iface_name argument is the name of the interface (e.g. fxp0).

Be verbose.
A host name or the IP address.


The arp utility displays and modifies the Internet-to-Ethernet address translation tables used by the Address Resolution Protocol (ARP).

With no options, the utility displays the current ARP entry for hostname. The host may be specified by name or by number, using Internet dot notation.


This utility is based on copyright software of The Regents of the University of California; for licensing information, see the Third Party License Terms List at