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 ] [ use ] [
14 managed ] [ extern_learn ]
15 ip neigh { show | flush } [ proxy ] [ to PREFIX ] [ dev DEV ] [ nud
17 STATE ] [ vrf NAME ] [ nomaster ]
18 ip neigh get ADDR dev DEV
20 STATE := { permanent | noarp | stale | reachable | none | incomplete |
22 delay | probe | failed }
23
26 The ip neigh command manipulates neighbour objects that establish bind‐
27 ings between protocol addresses and link layer addresses for hosts
28 sharing the same link. Neighbour entries are organized into tables.
29 The IPv4 neighbour table is also known by another name - the ARP table.
30 The corresponding commands display neighbour bindings and their proper‐
33 ties, add new neighbour entries and delete old ones.
34 ip neighbour add
37 add a new neighbour entry
38 ip neighbour change
40 change an existing entry
41 ip neighbour replace
43 add a new entry or change an existing one
44 These commands create new neighbour records or update existing
46 ones.
47 to ADDRESS (default)
50 the protocol address of the neighbour. It is either an
51 IPv4 or IPv6 address.
52 dev NAME
55 the interface to which this neighbour is attached.
56 proxy indicates whether we are proxying for this neighbour en‐
59 try
60 router indicates whether neighbour is a router
63 use this neigh entry is in "use". This option can be used to
66 indicate to the kernel that a controller is using this
67 dynamic entry. If the entry does not exist, the kernel
68 will resolve it. If it exists, an attempt to refresh the
69 neighbor entry will be triggered.
70 managed
73 this neigh entry is "managed". This option can be used to
74 indicate to the kernel that a controller is using this
75 dynamic entry. In contrast to "use", if the entry does
76 not exist, the kernel will resolve it and periodically
77 attempt to auto-refresh the neighbor entry such that it
78 remains in resolved state when possible.
79 extern_learn
82 this neigh entry was learned externally. This option can
83 be used to indicate to the kernel that this is a con‐
84 troller learnt dynamic entry. Kernel will not gc such an
85 entry.
86 lladdr LLADDRESS
89 the link layer address of the neighbour. LLADDRESS can
90 also be null.
91 nud STATE
94 the state of the neighbour entry. nud is an abbreviation
95 for 'Neighbour Unreachability Detection'. The state can
96 take one of the following values:
97 permanent
100 the neighbour entry is valid forever and can be
101 only be removed administratively.
102 noarp the neighbour entry is valid. No attempts to vali‐
104 date this entry will be made but it can be removed
105 when its lifetime expires.
106 reachable
108 the neighbour entry is valid until the reachabil‐
109 ity timeout expires.
110 stale the neighbour entry is valid but suspicious. This
112 option to ip neigh does not change the neighbour
113 state if it was valid and the address is not
114 changed by this command.
115 none this is a pseudo state used when initially creat‐
117 ing a neighbour entry or after trying to remove it
118 before it becomes free to do so.
119 incomplete
121 the neighbour entry has not (yet) been vali‐
122 dated/resolved.
123 delay neighbor entry validation is currently delayed.
125 probe neighbor is being probed.
127 failed max number of probes exceeded without success,
129 neighbor validation has ultimately failed.
130 ip neighbour delete
133 delete a neighbour entry
134 The arguments are the same as with ip neigh add, except that
136 lladdr and nud are ignored.
137 Warning: Attempts to delete or manually change a noarp entry
140 created by the kernel may result in unpredictable behaviour.
141 Particularly, the kernel may try to resolve this address even on
142 a NOARP interface or if the address is multicast or broadcast.
143 ip neighbour show
146 list neighbour entries
147 to ADDRESS (default)
149 the prefix selecting the neighbours to list.
150 dev NAME
153 only list the neighbours attached to this device.
154 vrf NAME
157 only list the neighbours for given VRF.
158 nomaster
161 only list neighbours attached to an interface with no
162 master.
163 proxy list neighbour proxies.
166 unused only list neighbours which are not currently in use.
169 nud STATE
172 only list neighbour entries in this state. NUD_STATE
173 takes values listed below or the special value all which
174 means all states. This option may occur more than once.
175 If this option is absent, ip lists all entries except for
176 none and noarp.
177 ip neighbour flush
180 flush neighbour entries
181 This command has the same arguments as show. The differences
182 are that it does not run when no arguments are given, and that
183 the default neighbour states to be flushed do not include perma‐
184 nent and noarp.
185 With the -statistics option, the command becomes verbose. It
188 prints out the number of deleted neighbours and the number of
189 rounds made to flush the neighbour table. If the option is given
190 twice, ip neigh flush also dumps all the deleted neighbours.
191 ip neigh get
194 lookup a neighbour entry to a destination given a device
195 proxy indicates whether we should lookup a proxy neighbour en‐
198 try
199 to ADDRESS (default)
202 the prefix selecting the neighbour to query.
203 dev NAME
206 get neighbour entry attached to this device.
207
210 ip neighbour
211 Shows the current neighbour table in kernel.
212 ip neigh flush dev eth0
214 Removes entries in the neighbour table on device eth0.
215 ip neigh get 10.0.1.10 dev eth0
217 Performs a neighbour lookup in the kernel and returns a neigh‐
218 bour entry.
219
222 ip(8)
223
226 Original Manpage by Michail Litvak <mci@owl.openwall.com>
227iproute2 20 Dec 2011 IP-NEIGHBOUR(8)