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.
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).
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.
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 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 184.108.40.206 and 220.127.116.11:
# arp -s 18.104.22.168 00:90:27:bb:cc:dd pub
# arp -s 22.214.171.124 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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