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 ] [ ex‐
14 tern_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 neighbour en‐
59 try
60 router indicates whether neighbour is a router
63 extern_learn
66 this neigh entry was learned externally. This option can
67 be used to indicate to the kernel that this is a con‐
68 troller learnt dynamic entry. Kernel will not gc such an
69 entry.
70 lladdr LLADDRESS
73 the link layer address of the neighbour. LLADDRESS can
74 also be null.
75 nud STATE
78 the state of the neighbour entry. nud is an abbreviation
79 for 'Neighbour Unreachability Detection'. The state can
80 take one of the following values:
81 permanent
84 the neighbour entry is valid forever and can be
85 only be removed administratively.
86 noarp the neighbour entry is valid. No attempts to vali‐
88 date this entry will be made but it can be removed
89 when its lifetime expires.
90 reachable
92 the neighbour entry is valid until the reachabil‐
93 ity timeout expires.
94 stale the neighbour entry is valid but suspicious. This
96 option to ip neigh does not change the neighbour
97 state if it was valid and the address is not
98 changed by this command.
99 none this is a pseudo state used when initially creat‐
101 ing a neighbour entry or after trying to remove it
102 before it becomes free to do so.
103 incomplete
105 the neighbour entry has not (yet) been vali‐
106 dated/resolved.
107 delay neighbor entry validation is currently delayed.
109 probe neighbor is being probed.
111 failed max number of probes exceeded without success,
113 neighbor validation has ultimately failed.
114 ip neighbour delete
117 delete a neighbour entry
118 The arguments are the same as with ip neigh add, except that
120 lladdr and nud are ignored.
121 Warning: Attempts to delete or manually change a noarp entry
124 created by the kernel may result in unpredictable behaviour.
125 Particularly, the kernel may try to resolve this address even on
126 a NOARP interface or if the address is multicast or broadcast.
127 ip neighbour show
130 list neighbour entries
131 to ADDRESS (default)
133 the prefix selecting the neighbours to list.
134 dev NAME
137 only list the neighbours attached to this device.
138 vrf NAME
141 only list the neighbours for given VRF.
142 proxy list neighbour proxies.
145 unused only list neighbours which are not currently in use.
148 nud STATE
151 only list neighbour entries in this state. NUD_STATE
152 takes values listed below or the special value all which
153 means all states. This option may occur more than once.
154 If this option is absent, ip lists all entries except for
155 none and noarp.
156 ip neighbour flush
159 flush neighbour entries
160 This command has the same arguments as show. The differences
161 are that it does not run when no arguments are given, and that
162 the default neighbour states to be flushed do not include perma‐
163 nent and noarp.
164 With the -statistics option, the command becomes verbose. It
167 prints out the number of deleted neighbours and the number of
168 rounds made to flush the neighbour table. If the option is given
169 twice, ip neigh flush also dumps all the deleted neighbours.
170 ip neigh get
173 lookup a neighbour entry to a destination given a device
174 proxy indicates whether we should lookup a proxy neighbour en‐
177 try
178 to ADDRESS (default)
181 the prefix selecting the neighbour to query.
182 dev NAME
185 get neighbour entry attached to this device.
186
189 ip neighbour
190 Shows the current neighbour table in kernel.
191 ip neigh flush dev eth0
193 Removes entries in the neighbour table on device eth0.
194 ip neigh get 10.0.1.10 dev eth0
196 Performs a neighbour lookup in the kernel and returns a neigh‐
197 bour entry.
198
201 ip(8)
202
205 Original Manpage by Michail Litvak <mci@owl.openwall.com>
206iproute2 20 Dec 2011 IP-NEIGHBOUR(8)