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 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 neigbour entry
59 router indicates whether neigbour is a router
62 extern_learn
65 this neigh entry was learned externally. This option can
66 be used to indicate to the kernel that this is a con‐
67 troller learnt dynamic entry. Kernel will not gc such an
68 entry.
69 lladdr LLADDRESS
72 the link layer address of the neighbour. LLADDRESS can
73 also be null.
74 nud STATE
77 the state of the neighbour entry. nud is an abbreviation
78 for 'Neighbour Unreachability Detection'. The state can
79 take one of the following values:
80 permanent
83 the neighbour entry is valid forever and can be
84 only be removed administratively.
85 noarp the neighbour entry is valid. No attempts to vali‐
87 date this entry will be made but it can be removed
88 when its lifetime expires.
89 reachable
91 the neighbour entry is valid until the reachabil‐
92 ity timeout expires.
93 stale the neighbour entry is valid but suspicious. This
95 option to ip neigh does not change the neighbour
96 state if it was valid and the address is not
97 changed by this command.
98 none this is a pseudo state used when initially creat‐
100 ing a neighbour entry or after trying to remove it
101 before it becomes free to do so.
102 incomplete
104 the neighbour entry has not (yet) been vali‐
105 dated/resolved.
106 delay neighbor entry validation is currently delayed.
108 probe neighbor is being probed.
110 failed max number of probes exceeded without success,
112 neighbor validation has ultimately failed.
113 ip neighbour delete
116 delete a neighbour entry
117 The arguments are the same as with ip neigh add, except that
119 lladdr and nud are ignored.
120 Warning: Attempts to delete or manually change a noarp entry
123 created by the kernel may result in unpredictable behaviour.
124 Particularly, the kernel may try to resolve this address even on
125 a NOARP interface or if the address is multicast or broadcast.
126 ip neighbour show
129 list neighbour entries
130 to ADDRESS (default)
132 the prefix selecting the neighbours to list.
133 dev NAME
136 only list the neighbours attached to this device.
137 vrf NAME
140 only list the neighbours for given VRF.
141 proxy list neighbour proxies.
144 unused only list neighbours which are not currently in use.
147 nud STATE
150 only list neighbour entries in this state. NUD_STATE
151 takes values listed below or the special value all which
152 means all states. This option may occur more than once.
153 If this option is absent, ip lists all entries except for
154 none and noarp.
155 ip neighbour flush
158 flush neighbour entries
159 This command has the same arguments as show. The differences
160 are that it does not run when no arguments are given, and that
161 the default neighbour states to be flushed do not include perma‐
162 nent and noarp.
163 With the -statistics option, the command becomes verbose. It
166 prints out the number of deleted neighbours and the number of
167 rounds made to flush the neighbour table. If the option is given
168 twice, ip neigh flush also dumps all the deleted neighbours.
169 ip neigh get
172 lookup a neighbour entry to a destination given a device
173 proxy indicates whether we should lookup a proxy neigbour entry
176 to ADDRESS (default)
179 the prefix selecting the neighbour to query.
180 dev NAME
183 get neighbour entry attached to this device.
184
187 ip neighbour
188 Shows the current neighbour table in kernel.
189 ip neigh flush dev eth0
191 Removes entries in the neighbour table on device eth0.
192 ip neigh get 10.0.1.10 dev eth0
194 Performs a neighbour lookup in the kernel and returns a neigh‐
195 bour entry.
196
199 ip(8)
200
203 Original Manpage by Michail Litvak <mci@owl.openwall.com>
204iproute2 20 Dec 2011 IP-NEIGHBOUR(8)