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.\" $DragonFly: src/usr.sbin/arp/arp.8,v 1.3 2006/01/19 22:19:31 dillon Exp $ 31.\" 32.Dd June 6, 1993 33.Dt ARP 8 34.Os 35.Sh NAME 36.Nm arp 37.Nd address resolution display and control 38.Sh SYNOPSIS 39.Nm 40.Op Fl n 41.Op Fl c Ar cpu 42.Ar hostname 43.Nm 44.Op Fl n 45.Op Fl c Ar cpu 46.Fl a 47.Nm 48.Fl d Ar hostname 49.Op Cm pub 50.Nm 51.Fl d 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 c Ar cpu 83On SMP systems the route table is replicated. This option allows 84the route table for a specific cpu to be accessed and exists 85primarily for debugging purposes. 86.It Fl d 87A super-user may delete an entry for the host called 88.Ar hostname 89with the 90.Fl d 91flag. 92If the 93.Cm pub 94keyword is specified, only the 95.Dq published 96.Tn ARP 97entry 98for this host will be deleted. 99.Pp 100Alternatively, the 101.Fl d 102flag may be combined with the 103.Fl a 104flag to delete all entries. 105.It Fl n 106Show network addresses as numbers (normally 107.Nm 108attempts to display addresses symbolically). 109.It Fl s Ar hostname ether_addr 110Create an 111.Tn ARP 112entry for the host called 113.Ar hostname 114with the Ethernet address 115.Ar ether_addr . 116The Ethernet address is given as six hex bytes separated by colons. 117The entry will be permanent unless the word 118.Cm temp 119is given in the command. 120If the word 121.Cm pub 122is given, the entry will be 123.Dq published ; 124i.e., this system will 125act as an 126.Tn ARP 127server, 128responding to requests for 129.Ar hostname 130even though the host address is not its own. 131In this case the 132.Ar ether_addr 133can be given as 134.Cm auto 135in which case the interfaces on this host will be examined, 136and if one of them is found to occupy the same subnet, its 137Ethernet address will be used. 138If the 139.Cm only 140keyword is also specified, this will create a 141.Dq "published (proxy only)" 142entry. 143This type of entry is created automatically if 144.Nm 145detects that a routing table entry for 146.Ar hostname 147already exists. 148.It Fl S Ar hostname ether_addr 149Is just like 150.Fl s 151except any existing 152.Tn ARP 153entry for this host will be deleted first. 154.It Fl f Ar filename 155Cause the file 156.Ar filename 157to be read and multiple entries to be set in the 158.Tn ARP 159tables. Entries 160in the file should be of the form 161.Pp 162.Bd -ragged -offset indent -compact 163.Ar hostname ether_addr 164.Op Cm temp 165.Op Cm pub 166.Ed 167.Pp 168with argument meanings as given above. 169Leading whitespace and empty lines are ignored. 170A 171.Ql # 172character will mark the rest of the line as a comment. 173.El 174.Sh SEE ALSO 175.Xr inet 3 , 176.Xr arp 4 , 177.Xr ifconfig 8 178.Sh HISTORY 179The 180.Nm 181utility appeared in 182.Bx 4.3 . 183