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

NAME
     arp - address resolution display and control

SYNOPSIS
     arp [-n] hostname
     arp [-n] -a
     arp -d hostname
     arp -d -a
     arp -s hostname ether_addr [temp | permanent] [pub]
     arp -f filename

DESCRIPTION
     The arp program displays and modifies the Internet-to-Ethernet address
     translation tables used by the address resolution protocol (arp(4)).
     With no flags, the program displays the current ARP entry for hostname.
     The host may be specified by name or by number, using Internet dot nota-
     tion.

     Available options:

     -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 filename
             Process entries from filename to be set in the ARP tables.  En-
             tries in the file should be of the form:

                   hostname ether_addr [temp | permanent] [pub]

             The entry will be static, i.e., 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 giv-
             en.  If the word pub is given, the entry will be ``published'';
             i.e., this system will act as an ARP server, responding to re-
             quests for hostname even though the host address is not its own.
             This behavior has traditionally been called proxy ARP.

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

     -s hostname ether_addr
             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.

EXAMPLES
     To view the current arp(4) table:

           $ arp -a

     To create a permanent entry (one that cannot be overwritten by other net-
     work traffic):

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

     To create proxy ARP entries on an interface, fxp0, for the 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

     (where 00:90:27:bb:cc:dd is the MAC address of fxp0)

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

HISTORY
     The arp command appeared in 4.3BSD.

OpenBSD 3.6                      July 14, 1999                               2