Tribblix: manual page: arp.8

ARP(8) Maintenance Commands and Procedures ARP(8)

NAME

arp - address resolution display and control

SYNOPSIS

arp hostname

arp -a [-n]

arp -d hostname

arp -f filename

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

DESCRIPTION

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 notation.

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).

OPTIONS

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

d
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 completes.

o
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.

y
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.

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

L
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.

M
Mapping; only used for the multicast entry for 224.0.0.0

P
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.

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

U
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

-d
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
deleted.

-f
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.

-s
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 configurations.

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.

NAME

SYNOPSIS

DESCRIPTION

OPTIONS

SEE ALSO