ARP(8)                  OpenBSD System Manager's Manual                 ARP(8)

NAME
     arp - address resolution display and control

SYNOPSIS
     arp [-adn] [-V rdomain] hostname
     arp [-F] [-f file] [-V rdomain] -s hostname ether_addr [temp | permanent]
         [pub]

DESCRIPTION
     The arp program displays and modifies the Internet-to-Ethernet address
     translation tables used by the address resolution protocol (ARP).

     arp displays the current ARP entry for hostname when no optional parame-
     ters are supplied.  hostname may be specified by name or by number, using
     Internet dot notation.

     The options are as follows:

     -a      Display all of the current ARP entries.  See also the -d option
             below.

     -d      Delete an entry for the host called hostname.  Alternatively, the
             -d flag may be combined with the -a flag to delete all entries,
             with hostname lookups automatically disabled.  Only the superuser
             may delete entries.

     -F      Force existing entries for the given host to be overwritten (only
             relevant to the -f and -s options).

     -f file
             Process entries from file to be set in the ARP tables.  Any en-
             tries in the file that already exist for a given host will not be
             overwritten unless -F is given.  Entries in the file should be of
             the form:

                   hostname ether_addr [temp | permanent] [pub]

             The entry will be static (will not time out) unless the word temp
             is given in the command.  A static ARP entry can be overwritten
             by network traffic, unless the word permanent is given.  If the
             word pub is given, the entry will be ``published''; that is, this
             system will act as an ARP server, responding to requests for
             hostname even though the host address is not its own.  This be-
             havior has traditionally been called proxy ARP.

     -n      Show network addresses as numbers (normally arp attempts to dis-
             play addresses symbolically).

     -s hostname ether_addr [temp | permanent] [pub]
             Create an ARP entry for the host called hostname with the Ether-
             net address ether_addr.  The Ethernet address is given as six
             hexadecimal bytes separated by colons.

             The permanent, pub, or temp modifiers may be specified with mean-
             ings as given above.

             If the entry already exists for the given host, it will not be
             replaced unless -F is given.

     -V rdomain
             Select the routing domain.  The default is 0.

EXAMPLES
     View the current arp(4) table, showing network addresses symbolically:

           $ arp -a

     Create a permanent entry (one that cannot be overwritten by other network
     traffic):

           # arp -s 10.0.0.2 00:90:27:bb:cc:dd permanent

     Create proxy ARP entries on interface fxp0 (MAC address
     00:90:27:bb:cc:dd), for IP addresses 204.1.2.3 and 204.1.2.4:

           # arp -s 204.1.2.3 00:90:27:bb:cc:dd pub
           # arp -s 204.1.2.4 00:90:27:bb:cc:dd pub

SEE ALSO
     inet(3), arp(4), ifconfig(8), ndp(8)

HISTORY
     The arp command appeared in 4.3BSD.

OpenBSD 4.7                      June 5, 2009                                2
