ARP(8) Maintenance Procedures ARP(8)


arp - address resolution display and control


arp hostname

arp -a [-n]

arp -d hostname

arp -f filename

arp -s hostname ether_address [temp] [pub] [trail]


The arp program displays and modifies the Internet-to-MAC address
translation tables used by the address resolution protocol (see arp(4P)).

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

Options that modify the ARP translation tables (-d, -f, and -s) can be
used only when the invoked command is granted the PRIV_SYS_NET_CONFIG
privilege. See privileges(7).


Display all of the current ARP entries. The definition for the
flags in the table are:

Unverified; this is a local IP address that is currently
undergoing Duplicate Address Detection. ARP will not respond
to requests for this address until Duplicate Address Detection

Old; this entry is aging away. If IP requests it again, a new
ARP query will be generated. This state is used for detecting
peer address changes.

Delayed; periodic address defense and conflict detection was
unable to send a packet due to internal network use limits for
non-traffic-related messages (100 packets per hour per
interface). This occurs only on interfaces with very large
numbers of aliases.

Authority; this machine is authoritative for this IP address.
ARP will not accept updates from other machines for this

Local; this is a local IP address configured on one of the
machine's logical interfaces. ARP will defend this address if
another node attempts to claim it.

Mapping; only used for the multicast entry for

Publish; includes IP address for the machine and the addresses
that have explicitly been added by the -s option. ARP will
respond to ARP requests for this address.

Static; entry cannot be changed by learned information. This
indicates that the permanent flag was used when creating the

Unresolved; waiting for ARP response.

You can use the -n option with the -a option to disable the
automatic numeric IP address-to-name translation. Use arp -an or
arp -na to display numeric IP addresses. The arp -a option is
equivalent to:

# netstat -p -f inet

...and -an and -na are equivalent to:

# netstat -pn -f inet

Delete an entry for the host called hostname.

Note that ARP entries for IPMP (IP Network Multipathing) data and
test addresses are managed by the kernel and thus cannot be

Read the file named filename and set multiple entries in the ARP
tables. Entries in the file should be of the form:

hostname MACaddress [temp] [pub] [trail] [permanent]

See the -s option for argument definitions.

Create an ARP entry for the host called hostname with the MAC
address MACaddress. For example, an Ethernet address is given as
six hexadecimal bytes separated by colons. The entry will not be
subject to deletion by aging unless the word temp is specified in
the command. If the word pub is specified, the entry will be
published, which means that this system will respond to ARP
requests for hostname even though the hostname is not its own. The
word permanent indicates that the system will not accept MAC
address changes for hostname from the network.

Solaris does not implement trailer encapsulation, and the word
trail is accepted on entries for compatibility only.

arp -s can be used for a limited form of proxy ARP when a host on
one of the directly attached networks is not physically present on
a subnet. Another machine can then be configured to respond to ARP
requests using arp -s. This is useful in certain SLIP

Non-temporary proxy ARP entries for an IPMP (IP Network
Multipathing) group are automatically managed by the kernel.
Specifically, if the hardware address in an entry matches the
hardware address of an IP interface in an IPMP group, and the IP
address is not local to the system, this will be regarded as an
IPMP proxy ARP entry. This entry will have its hardware address
automatically adjusted in order to keep the IP address reachable so
long as the IPMP group has not entirely failed.

ARP entries must be consistent across an IPMP group. Therefore, ARP
entries cannot be associated with individual underlying IP
interfaces in an IPMP group, and must instead be associated with
the corresponding IPMP IP interface.

Note that ARP entries for IPMP data and test addresses are managed
by the kernel and thus cannot be changed.


arp(4P), attributes(7), privileges(7), ifconfig(8), ndp(8), netstat(8)

September 2, 2015 ARP(8)