arp
Hurricane Electric Internet Services
NAME
arp - manipulate the system ARP cache
SYNOPSIS
arp [-v] [-t type] -a [hostname]
arp [-v] -d hostname ...
arp [-v] [-t type] -s hostname hw_addr [temp] [netmask
aa.bb.cc.dd] [pub]
arp [-v] -f filename
DESCRIPTION
Arp manipulates the kernel's ARP cache in various ways.
The primary options are clearing an address mapping entry
and manually setting up one. For debugging purposes, the
arp program also allows a complete dump of the ARP cache.
OPTIONS
-v Tell the user what is going on by being verbose.
-t type
When setting or reading the ARP cache, this
optional parameter tells arp which class of entries
it should check for. The default value of this
parameter is ether (i.e. hardware code 0x01 for
IEEE 802.3 10Mbps Ethernet ARCnet (arcnet) , PROnet
(pronet) and AX.25 (ax25)
-a [hostname]
Shows the entries of the specified hosts. If the
hostname parameter is not used, all entries will be
displayed.
-d hostname
Remove any entry for the specified host. This can
be used if the indicated host is brought down, for
example.
-s hostname hw_addr
Manually create an ARP address mapping entry for
host hostname with hardware address set to hw_addr
class, but for most classes one can assume that the
usual presentation can be used. For the Ethernet
class, this is 6 bytes in hexadecimal, separated by
colons. When adding proxy arp entries (that is
those with the [pub]lish flag set a netmask may be
specified to proxy arp for entire subnets. Proxy
arp for routing entire networks is not a good pro-
tocol, but its sometimes useful so supported.
-f filename
Similar to the -s option, only this time the
address info is taken from file filename set up.
The name of the data file is very often /etc/ethers
, but this is not official.
The format of the file is simple; it only contains
ASCII text lines with a hostname, and a hardware
address separated by whitespace.
In all places where a hostname is expected, one can also
enter an IP address in dotted-decimal notation.
FILES
/proc/net/arp,
/etc/ethers
AUTHOR
Fred N. van Kempen, <waltje@uwalt.nl.mugnet.org>
Hurricane Electric Internet Services
Copyright (C) 1998
Hurricane Electric.
All Rights Reserved.