1.\" Copyright (c) 1985, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 4. Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" @(#)arp.8 8.1 (Berkeley) 6/6/93 29.\" $FreeBSD$ 30.\" 31.Dd June 6, 1993 32.Dt ARP 8 33.Os 34.Sh NAME 35.Nm arp 36.Nd address resolution display and control 37.Sh SYNOPSIS 38.Nm 39.Op Fl n 40.Op Fl i Ar interface 41.Ar hostname 42.Nm 43.Op Fl n 44.Op Fl i Ar interface 45.Fl a 46.Nm 47.Fl d Ar hostname 48.Op Cm pub 49.Nm 50.Fl d 51.Op Fl i Ar interface 52.Fl a 53.Nm 54.Fl s Ar hostname ether_addr 55.Op Cm temp 56.Op Cm pub Op Cm only 57.Nm 58.Fl S Ar hostname ether_addr 59.Op Cm temp 60.Op Cm pub Op Cm only 61.Nm 62.Fl f Ar filename 63.Sh DESCRIPTION 64The 65.Nm 66utility displays and modifies the Internet-to-Ethernet address translation 67tables used by the address resolution protocol 68.Pq Xr arp 4 . 69With no flags, the program displays the current 70.Tn ARP 71entry for 72.Ar hostname . 73The host may be specified by name or by number, 74using Internet dot notation. 75.Pp 76Available options: 77.Bl -tag -width indent 78.It Fl a 79The program displays or deletes all of the current 80.Tn ARP 81entries. 82.It Fl d 83A super-user may delete an entry for the host called 84.Ar hostname 85with the 86.Fl d 87flag. 88If the 89.Cm pub 90keyword is specified, only the 91.Dq published 92.Tn ARP 93entry 94for this host will be deleted. 95.Pp 96Alternatively, the 97.Fl d 98flag may be combined with the 99.Fl a 100flag to delete all entries. 101.It Fl i Ar interface 102Limit the operation scope to the 103.Tn ARP 104entries on 105.Ar interface . 106Applicable to the display operations only. 107.It Fl n 108Show network addresses as numbers (normally 109.Nm 110attempts to display addresses symbolically). 111.It Fl s Ar hostname ether_addr 112Create an 113.Tn ARP 114entry for the host called 115.Ar hostname 116with the Ethernet address 117.Ar ether_addr . 118The Ethernet address is given as six hex bytes separated by colons. 119The entry will be permanent unless the word 120.Cm temp 121is given in the command. 122If the word 123.Cm pub 124is given, the entry will be 125.Dq published ; 126i.e., this system will 127act as an 128.Tn ARP 129server, 130responding to requests for 131.Ar hostname 132even though the host address is not its own. 133In this case the 134.Ar ether_addr 135can be given as 136.Cm auto 137in which case the interfaces on this host will be examined, 138and if one of them is found to occupy the same subnet, its 139Ethernet address will be used. 140If the 141.Cm only 142keyword is also specified, this will create a 143.Dq "published (proxy only)" 144entry. 145This type of entry is created automatically if 146.Nm 147detects that a routing table entry for 148.Ar hostname 149already exists. 150.It Fl S Ar hostname ether_addr 151Is just like 152.Fl s 153except any existing 154.Tn ARP 155entry for this host will be deleted first. 156.It Fl f Ar filename 157Cause the file 158.Ar filename 159to be read and multiple entries to be set in the 160.Tn ARP 161tables. 162Entries 163in the file should be of the form 164.Pp 165.Bd -ragged -offset indent -compact 166.Ar hostname ether_addr 167.Op Cm temp 168.Op Cm pub 169.Ed 170.Pp 171with argument meanings as given above. 172Leading whitespace and empty lines are ignored. 173A 174.Ql # 175character will mark the rest of the line as a comment. 176.El 177.Sh SEE ALSO 178.Xr inet 3 , 179.Xr arp 4 , 180.Xr ifconfig 8 181.Sh HISTORY 182The 183.Nm 184utility appeared in 185.Bx 4.3 . 186