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


     arp - address resolution display and control


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


     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
     parameters are supplied.  hostname may be specified by name or by number,
     using Internet dot notation.

     arp can also be used to send Wake on LAN (WoL) frames over a local
     Ethernet network to one or more hosts using their link layer (hardware)
     addresses.  WoL functionality is generally enabled in a machine's BIOS
     and can be used to power on machines from a remote system without having
     physical access to them.

     The options are as follows:

     -a      Display all of the current ARP entries.  See also the -d option
             below.  The following information will be printed:

                Host    The network address of the host.

                Ethernet Address
                        The Ethernet address of the host.  If the address is
                        not available, it will be displayed as "(incomplete)".

                Netif   The network interface associated with the ARP entry.

                Expire  The time until expiry of the entry.  If the entry is
                        marked "permanent" or "static", it will never expire.

                Flags   Flags on the ARP entry, in a single letter.  They are:
                        local (`l') and published (`p').

     -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.  See the
             -s option for a description of the file format and the effect of
             the -F option.

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

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

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

     -V rdomain
             Select the routing domain.

     -W ether_addr [iface]
             Send the Wake on LAN frame from all interfaces on the local
             machine that are up, if iface has not been specified.  Otherwise
             the frame will be sent from iface.  ether_addr is the Ethernet
             address of the remote machine or a hostname entry in /etc/ethers.
             This option cannot be used in combination with any other option.


     /etc/ethers  Ethernet host name database.


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

           $ arp -a

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

           # arp -s 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 and

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


     inet_addr(3), arp(4), ethers(5), ifconfig(8), ndp(8)


     The arp command appeared in 4.3BSD.  Wake on LAN functionality was added
     in OpenBSD 4.9.

OpenBSD 6.2                      April 5, 2016                     OpenBSD 6.2

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