1IP-NEIGHBOUR(8)                      Linux                     IP-NEIGHBOUR(8)
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NAME

6       ip-neighbour - neighbour/arp tables management.
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SYNOPSIS

9       ip [ OPTIONS ] neigh  { COMMAND | help }
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12       ip neigh { add | del | change | replace } { ADDR [ lladdr LLADDR ] [
13               nud STATE ] | proxy ADDR } [ dev DEV ]
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15       ip neigh { show | flush } [ proxy ] [ to PREFIX ] [ dev DEV ] [ nud
16               STATE ] [ vrf NAME ]
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18       STATE := { permanent | noarp | stale | reachable | none | incomplete |
19               delay | probe | failed }
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DESCRIPTION

23       The ip neigh command manipulates neighbour objects that establish bind‐
24       ings between protocol addresses and link layer addresses for hosts
25       sharing the same link.  Neighbour entries are organized into tables.
26       The IPv4 neighbour table is also known by another name - the ARP table.
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29       The corresponding commands display neighbour bindings and their proper‐
30       ties, add new neighbour entries and delete old ones.
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33       ip neighbour add
34              add a new neighbour entry
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36       ip neighbour change
37              change an existing entry
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39       ip neighbour replace
40              add a new entry or change an existing one
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42              These commands create new neighbour records or update existing
43              ones.
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46              to ADDRESS (default)
47                     the protocol address of the neighbour. It is either an
48                     IPv4 or IPv6 address.
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51              dev NAME
52                     the interface to which this neighbour is attached.
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55              lladdr LLADDRESS
56                     the link layer address of the neighbour.  LLADDRESS can
57                     also be null.
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60              nud STATE
61                     the state of the neighbour entry.  nud is an abbreviation
62                     for 'Neighbour Unreachability Detection'.  The state can
63                     take one of the following values:
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66                     permanent
67                            the neighbour entry is valid forever and can be
68                            only be removed administratively.
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70                     noarp  the neighbour entry is valid. No attempts to vali‐
71                            date this entry will be made but it can be removed
72                            when its lifetime expires.
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74                     reachable
75                            the neighbour entry is valid until the reachabil‐
76                            ity timeout expires.
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78                     stale  the neighbour entry is valid but suspicious.  This
79                            option to ip neigh does not change the neighbour
80                            state if it was valid and the address is not
81                            changed by this command.
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83                     none   this is a pseudo state used when initially creat‐
84                            ing a neighbour entry or after trying to remove it
85                            before it becomes free to do so.
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87                     incomplete
88                            the neighbour entry has not (yet) been vali‐
89                            dated/resolved.
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91                     delay  neighbor entry validation is currently delayed.
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93                     probe  neighbor is being probed.
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95                     failed max number of probes exceeded without success,
96                            neighbor validation has ultimately failed.
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99       ip neighbour delete
100              delete a neighbour entry
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102              The arguments are the same as with ip neigh add, except that
103              lladdr and nud are ignored.
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106              Warning: Attempts to delete or manually change a noarp entry
107              created by the kernel may result in unpredictable behaviour.
108              Particularly, the kernel may try to resolve this address even on
109              a NOARP interface or if the address is multicast or broadcast.
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112       ip neighbour show
113              list neighbour entries
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115              to ADDRESS (default)
116                     the prefix selecting the neighbours to list.
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119              dev NAME
120                     only list the neighbours attached to this device.
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123              vrf NAME
124                     only list the neighbours for given VRF.
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127              proxy  list neighbour proxies.
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130              unused only list neighbours which are not currently in use.
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133              nud STATE
134                     only list neighbour entries in this state.  NUD_STATE
135                     takes values listed below or the special value all which
136                     means all states. This option may occur more than once.
137                     If this option is absent, ip lists all entries except for
138                     none and noarp.
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141       ip neighbour flush
142              flush neighbour entries
143              This command has the same arguments as show.  The differences
144              are that it does not run when no arguments are given, and that
145              the default neighbour states to be flushed do not include perma‐
146              nent and noarp.
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149              With the -statistics option, the command becomes verbose. It
150              prints out the number of deleted neighbours and the number of
151              rounds made to flush the neighbour table. If the option is given
152              twice, ip neigh flush also dumps all the deleted neighbours.
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EXAMPLES

156       ip neighbour
157              Shows the current neighbour table in kernel.
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159       ip neigh flush dev eth0
160              Removes entries in the neighbour table on device eth0.
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SEE ALSO

164       ip(8)
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AUTHOR

168       Original Manpage by Michail Litvak <mci@owl.openwall.com>
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172iproute2                          20 Dec 2011                  IP-NEIGHBOUR(8)
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