arp(ADMN)

Syntax

arp -a [ -n ]

arp -d [ -n ] hostname

arp -f [ -n ] filename

arp -s [ -n ] hostname ether_addr [ temp] [ pub ]

arp -S

Description

When hostname is the only argument, arp displays the current ARP entry for hostname. The host may be specified by name or by number, using Internet dot notation (see hosts(SFF) and inet(ADMP)).

Options are interpreted as follows:

-a

Display all of the current ARP entries by reading the table from the kernel.

-d

Delete an entry for the host whose name is hostname. (This can be performed only by the root.)

-f filename

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

hostname ether_addr [ temp ] [ pub ]

with argument meanings as defined under the -s option.

-s hostname ether_addr [ temp ] [ pub ]

Create an ARP entry for the host whose name is hostname with the Ethernet address ether_addr. The Ethernet address is given as six colon-separated, two-digit hexadecimal numbers. The entry will be permanent unless the argument temp is specified on the command line. If pub is specified, 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 an address of the local host.

-S

Displays the ARP statistics that the kernel maintains; these may be useful for debugging network problems.

Diagnostics

   WARNING: arp: info overwritten for IP_address by MAC_address

• two or more systems having the same IP address on the local network. This is likely to be the case if you see the error message repeated several times on a single system. Redefine the IP address of one of the systems using the scoadmin(ADM) Network Configuration Manager or netconfig(ADM).

• changing a network card in a system. The message should only occur at most once on each of the other systems connected to the local network.

See also

RFC 826 (STD 37)