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