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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 deletes all of the current
94 A super-user may delete an entry for the host called
101 keyword is specified, only the
105 for this host will be deleted.
109 flag may be combined with the
111 flag to delete all entries.
112 .It Fl i Ar interface
113 Limit the operation scope to the
117 Applicable only to the following operations:
118 display one, display all, delete all.
120 Show network addresses as numbers (normally
122 attempts to display addresses symbolically).
123 .It Fl s Ar hostname ether_addr
126 entry for the host called
128 with the Ethernet address
130 The Ethernet address is given as six hex bytes separated by colons.
131 The entry will be permanent unless the word
133 is given in the command.
136 is given, the entry will be
138 i.e., this system will
142 responding to requests for
144 even though the host address is not its own.
149 in which case the interfaces on this host will be examined,
150 and if one of them is found to occupy the same subnet, its
151 Ethernet address will be used.
155 keyword is specified the entry will be marked so that traffic to
156 the host will be discarded and the sender will be notified the
160 keyword is similar in that traffic is discarded but the sender is
162 These can be used to block external traffic to a host without
164 .It Fl S Ar hostname ether_addr
169 entry for this host will be deleted first.
173 to be read and multiple entries to be set in the
177 in the file should be of the form
179 .Bd -ragged -offset indent -compact
180 .Ar hostname ether_addr
182 .Op Cm blackhole No \&| Cm reject
186 with argument meanings as given above.
187 Leading whitespace and empty lines are ignored.
190 character will mark the rest of the line as a comment.
195 .Xr xo_parse_args 3 ,