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28 .\" @(#)arp.8 8.1 (Berkeley) 6/6/93
35 .Nd address resolution display and control
38 .Op Fl -libxo Ar options
43 .Op Fl -libxo Ar options
55 .Fl s Ar hostname ether_addr
57 .Op Cm blackhole No \&| Cm reject
60 .Fl S Ar hostname ether_addr
62 .Op Cm blackhole No \&| Cm reject
69 utility displays and modifies the Internet-to-Ethernet address translation
70 tables used by the address resolution protocol
72 With no flags, the program displays the current
76 The host may be specified by name or by number,
77 using Internet dot notation.
80 .Bl -tag -width indent
84 in a selection of different human and machine readable formats.
87 for details on command line arguments.
89 The program displays or, if it is used with the
91 flag, deletes all of the current
95 A super-user may delete an entry for the host called
102 keyword is specified, only the
106 for this host will be deleted.
110 flag may be combined with the
112 flag to delete all entries.
113 .It Fl i Ar interface
114 Limit the operation scope to the
118 Applicable only to the following operations:
119 display one, display all, delete all.
121 Show network addresses as numbers (normally
123 attempts to display addresses symbolically).
124 .It Fl s Ar hostname ether_addr
127 entry for the host called
129 with the Ethernet address
131 The Ethernet address is given as six hex bytes separated by colons.
132 The entry will be permanent unless the word
134 is given in the command.
137 is given, the entry will be
139 i.e., this system will
143 responding to requests for
145 even though the host address is not its own.
150 in which case the interfaces on this host will be examined,
151 and if one of them is found to occupy the same subnet, its
152 Ethernet address will be used.
156 keyword is specified the entry will be marked so that traffic to
157 the host will be discarded and the sender will be notified the
161 keyword is similar in that traffic is discarded but the sender is
163 These can be used to block external traffic to a host without
165 .It Fl S Ar hostname ether_addr
170 entry for this host will be deleted first.
174 to be read and multiple entries to be set in the
178 in the file should be of the form
180 .Bd -ragged -offset indent -compact
181 .Ar hostname ether_addr
183 .Op Cm blackhole No \&| Cm reject
187 with argument meanings as given above.
188 Leading whitespace and empty lines are ignored.
191 character will mark the rest of the line as a comment.
196 .Xr xo_parse_args 3 ,