NetBSD/usr.sbin/arp/arp.8

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.\"	from: @(#)arp.8	8.2 (Berkeley) 4/27/95
.\"
.Dd December 5, 2021
.Dt ARP 8
.Os
.Sh NAME
.Nm arp
.Nd address resolution display and control
.Sh SYNOPSIS
.Nm
.Op Fl n
.Ar hostname
.Nm
.Op Fl nv
.Fl a
.Nm
.Op Fl v
.Fl d
.Fl a
.Nm
.Op Fl v
.Fl d Ar hostname
.Op Cm proxy
.Nm
.Fl s Ar hostname ether_addr
.Op Cm temp
.Op Cm pub Op Cm proxy
.Nm
.Fl f Ar filename
.Sh DESCRIPTION
The
.Nm
program displays and modifies the Internet-to-Ethernet address translation
tables used by the address resolution protocol
.Pq Xr arp 4 .
With no flags, the program displays the current
.Tn ARP
entry for
.Ar hostname .
The host may be specified by name or by number,
using Internet dot notation.
.Pp
The state of the arp entry is shown as a single letter preceded by the
time the state is applicable for:
.Bl -tag -width indent -compact
.It D
Delay
.It I
Incomplete
.It N
Nostate
.It P
Probe
.It R
Reachable
.It S
Stale
.It U
Unreachable
.It W
Waitdelete
.It ?
Unknown state (should never happen).
.El
.Pp
Available options:
.Bl -tag -width Ds
.It Fl a
The program displays all of the current
.Tn ARP
entries.
.It Fl d
A super-user may delete an entry for the host called
.Ar hostname
with the
.Fl d
flag.
If the
.Cm proxy
keyword is specified, only the published
.Dq proxy only
.Tn ARP
entry
for this host will be deleted.
If used with
.Fl a
instead of a
.Ar hostname ,
it will delete all arp entries.
.It Fl f
Causes the file
.Ar filename
to be read and multiple entries to be set in the
.Tn ARP
tables.
Entries in the file should be of the form
.Pp
.Bd -filled -offset indent -compact
.Ar hostname ether_addr
.Op Cm temp
.Op Cm pub
.Ed
.Pp
with argument meanings as described below.
.It Fl n
Show network addresses as numbers (normally
.Nm
attempts to display addresses symbolically).
.It Fl s Ar hostname ether_addr
Create an
.Tn ARP
entry for the host called
.Ar hostname
with the Ethernet address
.Ar ether_addr .
The Ethernet address is given as six hex bytes separated by colons.
The entry will be permanent unless the word
.Cm temp
is given in the command.
If the word
.Cm pub
is given, the entry will be "published"; i.e., this system will
act as an
.Tn ARP
server,
responding to requests for
.Ar hostname
even though the host address is not its own.
.Pp
If the word
.Cm proxy
is also given, the published entry will be a
.Dq proxy only
entry.
In this case the
.Ar ether_addr
can be given as
.Cm auto
in which case the interfaces on this host will be examined,
and if one of them is found to occupy the same subnet, its
Ethernet address will be used.
.It Fl v
Display verbose information when adding or deleting
.Tn ARP
entries.
.El
.Sh SEE ALSO
.Xr inet 3 ,
.Xr arp 4 ,
.Xr ifconfig 8
.Sh HISTORY
The
.Nm
command appeared in
.Bx 4.3 .