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.\" 3. 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: src/usr.sbin/arp/arp.8,v 1.8.2.11 2003/03/11 21:13:48 trhodes Exp $ 30.\" 31.Dd October 25, 2018 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 c Ar cpu 41.Op Fl i Ar interface 42.Ar hostname 43.Nm 44.Op Fl n 45.Op Fl c Ar cpu 46.Op Fl i Ar interface 47.Fl a 48.Nm 49.Fl d Ar hostname 50.Op Cm pub 51.Nm 52.Fl d 53.Op Fl i Ar interface 54.Fl a 55.Nm 56.Fl s Ar hostname ether_addr 57.Op Cm temp 58.Op Cm pub Op Cm only 59.Nm 60.Fl S Ar hostname ether_addr 61.Op Cm temp 62.Op Cm pub Op Cm only 63.Nm 64.Fl f Ar filename 65.Sh DESCRIPTION 66The 67.Nm 68utility displays and modifies the Internet-to-Ethernet address translation 69tables used by the address resolution protocol 70.Pq Xr arp 4 . 71With no flags, the program displays the current 72.Tn ARP 73entry for 74.Ar hostname . 75The host may be specified by name or by number, 76using Internet dot notation. 77.Pp 78Available options: 79.Bl -tag -width indent 80.It Fl a 81The program displays or deletes all of the current 82.Tn ARP 83entries. 84.It Fl c Ar cpu 85On SMP systems the route table is replicated. This option allows 86the route table for a specific cpu to be accessed and exists 87primarily for debugging purposes. 88.It Fl d 89A super-user may delete an entry for the host called 90.Ar hostname 91with the 92.Fl d 93flag. 94If the 95.Cm pub 96keyword is specified, only the 97.Dq published 98.Tn ARP 99entry 100for this host will be deleted. 101.Pp 102Alternatively, the 103.Fl d 104flag may be combined with the 105.Fl a 106flag to delete all entries. 107.It Fl i Ar interface 108Limit the operation scope to the 109.Tn ARP 110entries on 111.Ar interface . 112Applicable only to the following operations: 113display one, display all, delete all. 114.It Fl n 115Show network addresses as numbers (normally 116.Nm 117attempts to display addresses symbolically). 118.It Fl s Ar hostname ether_addr 119Create an 120.Tn ARP 121entry for the host called 122.Ar hostname 123with the Ethernet address 124.Ar ether_addr . 125The Ethernet address is given as six hex bytes separated by colons. 126The entry will be permanent unless the word 127.Cm temp 128is given in the command. 129If the word 130.Cm pub 131is given, the entry will be 132.Dq published ; 133i.e., this system will 134act as an 135.Tn ARP 136server, 137responding to requests for 138.Ar hostname 139even though the host address is not its own. 140In this case the 141.Ar ether_addr 142can be given as 143.Cm auto 144in which case the interfaces on this host will be examined, 145and if one of them is found to occupy the same subnet, its 146Ethernet address will be used. 147If the 148.Cm only 149keyword is also specified, this will create a 150.Dq "published (proxy only)" 151entry. 152This type of entry is created automatically if 153.Nm 154detects that a routing table entry for 155.Ar hostname 156already exists. 157.It Fl S Ar hostname ether_addr 158Is just like 159.Fl s 160except any existing 161.Tn ARP 162entry for this host will be deleted first. 163.It Fl f Ar filename 164Cause the file 165.Ar filename 166to be read and multiple entries to be set in the 167.Tn ARP 168tables. Entries 169in the file should be of the form 170.Pp 171.Bd -ragged -offset indent -compact 172.Ar hostname ether_addr 173.Op Cm temp 174.Op Cm pub 175.Ed 176.Pp 177with argument meanings as given above. 178Leading whitespace and empty lines are ignored. 179A 180.Ql # 181character will mark the rest of the line as a comment. 182.El 183.Sh SEE ALSO 184.Xr inet 3 , 185.Xr arp 4 , 186.Xr ifconfig 8 187.Sh HISTORY 188The 189.Nm 190utility appeared in 191.Bx 4.3 . 192