.TH ARP 3 
.SH NAME
arp \- Internet Address Resolution Protocol
.SH SYNOPSIS
.nf
.B bind \-a #a /net/arp
.sp
.B /net/arp/ctl
.B /net/arp/data
.B /net/arp/stats
.fi
.SH DESCRIPTION
The
.I arp
device provides the means by which the kernel resolves
IP addresses
into Ethernet addresses.
A cache is maintained by the
.B arp
device to speed the process.
.PP
The
.B ctl
file controls the ARP cache maintained by the kernel.
The
.B flush
control message invalidates all entries in the cache.
The
.B delete
.I ipaddr
control message invalidates a single cache entry.
.PP
The
.B data
file provides two interfaces.
The first open of the
.B data
file connects the
.B arpd
server to the kernel ARP cache
(see
.IR ipconfig (8)).
.B Arpd
writes the results of address resolution requests from the kernel back into the
.B data
file to prime the cache.
Subsequent opens of the
.B data
file allow the contents of the cache to be read.
Each cache entry consists of an
IP address, an Ethernet address and the status of the entry.
Entries may be
invalid, permanent or temporary.
Permanent entries will never be aged from the cache.
Temporary entries may be replaced by new addresses entered by the ARP server.
.PP
The file
.B stats
reports the cache performance.
.EE
.SH SEE ALSO
.IR ip (3),
.IR ipconfig (8)