1 .\" Copyright (c) 1985, 1991, 1993
2 .\" The Regents of the University of California. All rights reserved.
4 .\" Redistribution and use in source and binary forms, with or without
5 .\" modification, are permitted provided that the following conditions
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.
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
28 .\" @(#)arp.8 8.1 (Berkeley) 6/6/93
36 .Nd address resolution display and control
39 .Op Fl -libxo Ar options
44 .Op Fl -libxo Ar options
56 .Fl s Ar hostname ether_addr
58 .Op Cm blackhole No \&| Cm reject
61 .Fl S Ar hostname ether_addr
63 .Op Cm blackhole No \&| Cm reject
70 utility displays and modifies the Internet-to-Ethernet address translation
71 tables used by the address resolution protocol
73 With no flags, the program displays the current
77 The host may be specified by name or by number,
78 using Internet dot notation.
81 .Bl -tag -width indent
85 in a selection of different human and machine readable formats.
88 for details on command line arguments.
90 The program displays or, if it is used with the
92 flag, deletes all of the current
96 A super-user may delete an entry for the host called
103 keyword is specified, only the
107 for this host will be deleted.
111 flag may be combined with the
113 flag to delete all entries.
114 .It Fl i Ar interface
115 Limit the operation scope to the
119 Applicable only to the following operations:
120 display one, display all, delete all.
122 Show network addresses as numbers (normally
124 attempts to display addresses symbolically).
125 .It Fl s Ar hostname ether_addr
128 entry for the host called
130 with the Ethernet address
132 The Ethernet address is given as six hex bytes separated by colons.
133 The entry will be permanent unless the word
135 is given in the command.
138 is given, the entry will be
140 i.e., this system will
144 responding to requests for
146 even though the host address is not its own.
151 in which case the interfaces on this host will be examined,
152 and if one of them is found to occupy the same subnet, its
153 Ethernet address will be used.
157 keyword is specified the entry will be marked so that traffic to
158 the host will be discarded and the sender will be notified the
162 keyword is similar in that traffic is discarded but the sender is
164 These can be used to block external traffic to a host without
166 .It Fl S Ar hostname ether_addr
171 entry for this host will be deleted first.
175 to be read and multiple entries to be set in the
179 in the file should be of the form
181 .Bd -ragged -offset indent -compact
182 .Ar hostname ether_addr
184 .Op Cm blackhole No \&| Cm reject
188 with argument meanings as given above.
189 Leading whitespace and empty lines are ignored.
192 character will mark the rest of the line as a comment.
197 .Xr xo_parse_args 3 ,