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 August 17, 2006 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 only to the following operations: 107display one, display all, delete all. 108.It Fl n 109Show network addresses as numbers (normally 110.Nm 111attempts to display addresses symbolically). 112.It Fl s Ar hostname ether_addr 113Create an 114.Tn ARP 115entry for the host called 116.Ar hostname 117with the Ethernet address 118.Ar ether_addr . 119The Ethernet address is given as six hex bytes separated by colons. 120The entry will be permanent unless the word 121.Cm temp 122is given in the command. 123If the word 124.Cm pub 125is given, the entry will be 126.Dq published ; 127i.e., this system will 128act as an 129.Tn ARP 130server, 131responding to requests for 132.Ar hostname 133even though the host address is not its own. 134In this case the 135.Ar ether_addr 136can be given as 137.Cm auto 138in which case the interfaces on this host will be examined, 139and if one of them is found to occupy the same subnet, its 140Ethernet address will be used. 141If the 142.Cm only 143keyword is also specified, this will create a 144.Dq "published (proxy only)" 145entry. 146This type of entry is created automatically if 147.Nm 148detects that a routing table entry for 149.Ar hostname 150already exists. 151.It Fl S Ar hostname ether_addr 152Is just like 153.Fl s 154except any existing 155.Tn ARP 156entry for this host will be deleted first. 157.It Fl f Ar filename 158Cause the file 159.Ar filename 160to be read and multiple entries to be set in the 161.Tn ARP 162tables. 163Entries 164in the file should be of the form 165.Pp 166.Bd -ragged -offset indent -compact 167.Ar hostname ether_addr 168.Op Cm temp 169.Op Cm pub 170.Ed 171.Pp 172with argument meanings as given above. 173Leading whitespace and empty lines are ignored. 174A 175.Ql # 176character will mark the rest of the line as a comment. 177.El 178.Sh SEE ALSO 179.Xr inet 3 , 180.Xr arp 4 , 181.Xr ifconfig 8 182.Sh HISTORY 183The 184.Nm 185utility appeared in 186.Bx 4.3 . 187