1IP-NEIGHBOUR(8) Linux IP-NEIGHBOUR(8)
2
6 ip-neighbour - neighbour/arp tables management.
7
9 ip [ OPTIONS ] neigh { COMMAND | help }
10 ip neigh { add | del | change | replace } { ADDR [ lladdr LLADDR ] [
13 nud STATE ] | proxy ADDR } [ dev DEV ] [ router ] [
14 extern_learn ]
15 ip neigh { show | flush } [ proxy ] [ to PREFIX ] [ dev DEV ] [ nud
17 STATE ] [ vrf NAME ]
18 STATE := { permanent | noarp | stale | reachable | none | incomplete |
20 delay | probe | failed }
21
24 The ip neigh command manipulates neighbour objects that establish bind‐
25 ings between protocol addresses and link layer addresses for hosts
26 sharing the same link. Neighbour entries are organized into tables.
27 The IPv4 neighbour table is also known by another name - the ARP table.
28 The corresponding commands display neighbour bindings and their proper‐
31 ties, add new neighbour entries and delete old ones.
32 ip neighbour add
35 add a new neighbour entry
36 ip neighbour change
38 change an existing entry
39 ip neighbour replace
41 add a new entry or change an existing one
42 These commands create new neighbour records or update existing
44 ones.
45 to ADDRESS (default)
48 the protocol address of the neighbour. It is either an
49 IPv4 or IPv6 address.
50 dev NAME
53 the interface to which this neighbour is attached.
54 proxy indicates whether we are proxying for this neigbour entry
57 router indicates whether neigbour is a router
60 extern_learn
63 this neigh entry was learned externally. This option can
64 be used to indicate to the kernel that this is a con‐
65 troller learnt dynamic entry. Kernel will not gc such an
66 entry.
67 lladdr LLADDRESS
70 the link layer address of the neighbour. LLADDRESS can
71 also be null.
72 nud STATE
75 the state of the neighbour entry. nud is an abbreviation
76 for 'Neighbour Unreachability Detection'. The state can
77 take one of the following values:
78 permanent
81 the neighbour entry is valid forever and can be
82 only be removed administratively.
83 noarp the neighbour entry is valid. No attempts to vali‐
85 date this entry will be made but it can be removed
86 when its lifetime expires.
87 reachable
89 the neighbour entry is valid until the reachabil‐
90 ity timeout expires.
91 stale the neighbour entry is valid but suspicious. This
93 option to ip neigh does not change the neighbour
94 state if it was valid and the address is not
95 changed by this command.
96 none this is a pseudo state used when initially creat‐
98 ing a neighbour entry or after trying to remove it
99 before it becomes free to do so.
100 incomplete
102 the neighbour entry has not (yet) been vali‐
103 dated/resolved.
104 delay neighbor entry validation is currently delayed.
106 probe neighbor is being probed.
108 failed max number of probes exceeded without success,
110 neighbor validation has ultimately failed.
111 ip neighbour delete
114 delete a neighbour entry
115 The arguments are the same as with ip neigh add, except that
117 lladdr and nud are ignored.
118 Warning: Attempts to delete or manually change a noarp entry
121 created by the kernel may result in unpredictable behaviour.
122 Particularly, the kernel may try to resolve this address even on
123 a NOARP interface or if the address is multicast or broadcast.
124 ip neighbour show
127 list neighbour entries
128 to ADDRESS (default)
130 the prefix selecting the neighbours to list.
131 dev NAME
134 only list the neighbours attached to this device.
135 vrf NAME
138 only list the neighbours for given VRF.
139 proxy list neighbour proxies.
142 unused only list neighbours which are not currently in use.
145 nud STATE
148 only list neighbour entries in this state. NUD_STATE
149 takes values listed below or the special value all which
150 means all states. This option may occur more than once.
151 If this option is absent, ip lists all entries except for
152 none and noarp.
153 ip neighbour flush
156 flush neighbour entries
157 This command has the same arguments as show. The differences
158 are that it does not run when no arguments are given, and that
159 the default neighbour states to be flushed do not include perma‐
160 nent and noarp.
161 With the -statistics option, the command becomes verbose. It
164 prints out the number of deleted neighbours and the number of
165 rounds made to flush the neighbour table. If the option is given
166 twice, ip neigh flush also dumps all the deleted neighbours.
167
170 ip neighbour
171 Shows the current neighbour table in kernel.
172 ip neigh flush dev eth0
174 Removes entries in the neighbour table on device eth0.
175
178 ip(8)
179
182 Original Manpage by Michail Litvak <mci@owl.openwall.com>
183iproute2 20 Dec 2011 IP-NEIGHBOUR(8)