The ip neigh command manipulates neighbour objects that establish
bindings between protocol addresses and link layer addresses for
hosts sharing the same link. Neighbour entries are organized into
tables. The IPv4 neighbour table is also known by another name - the
The corresponding commands display neighbour bindings and their
properties, add new neighbour entries and delete old ones.
ip neighbour add
add a new neighbour entry
ip neighbour change
change an existing entry
ip neighbour replace
add a new entry or change an existing one
These commands create new neighbour records or update existing
the protocol address of the neighbour. It is either an
IPv4 or IPv6 address.
the interface to which this neighbour is attached.
the link layer address of the neighbour. LLADDRESS can
also be null.
the state of the neighbour entry. nud is an
abbreviation for 'Neighbour Unreachability Detection'.
The state can take one of the following values:
the neighbour entry is valid forever and can be
only be removed administratively.
noarp the neighbour entry is valid. No attempts to
validate this entry will be made but it can be
removed when its lifetime expires.
the neighbour entry is valid until the
reachability timeout expires.
stale the neighbour entry is valid but suspicious.
This option to ip neigh does not change the
neighbour state if it was valid and the address
is not changed by this command.
none this is a pseudo state used when initially
creating a neighbour entry or after trying to
remove it before it becomes free to do so.
the neighbour entry has not (yet) been
delay neighbor entry validation is currently delayed.
probe neighbor is being probed.
failed max number of probes exceeded without success,
neighbor validation has ultimately failed.
ip neighbour delete
delete a neighbour entry
The arguments are the same as with ip neigh add, except that
lladdr and nud are ignored.
Warning: Attempts to delete or manually change a noarp entry
created by the kernel may result in unpredictable behaviour.
Particularly, the kernel may try to resolve this address even
on a NOARP interface or if the address is multicast or
ip neighbour show
list neighbour entries
the prefix selecting the neighbours to list.
only list the neighbours attached to this device.
only list the neighbours for given VRF.
proxy list neighbour proxies.
unused only list neighbours which are not currently in use.
only list neighbour entries in this state. NUD_STATE
takes values listed below or the special value all
which means all states. This option may occur more than
once. If this option is absent, ip lists all entries
except for none and noarp.
ip neighbour flush
flush neighbour entries
This command has the same arguments as show. The differences
are that it does not run when no arguments are given, and that
the default neighbour states to be flushed do not include
permanent and noarp.
With the -statistics option, the command becomes verbose. It
prints out the number of deleted neighbours and the number of
rounds made to flush the neighbour table. If the option is
given twice, ip neigh flush also dumps all the deleted
This page is part of the iproute2 (utilities for controlling TCP/IP
networking and traffic) project. Information about the project can
be found at
If you have a bug report for this manual page, send it to
firstname.lastname@example.org, email@example.com. This page was obtained
from the project's upstream Git repository
on 2017-03-13. If you discover any rendering problems in this HTML
version of the page, or you believe there is a better or more up-to-
date source for the page, or you have corrections or improvements to
the information in this COLOPHON (which is not part of the original
manual page), send a mail to firstname.lastname@example.org
iproute2 20 Dec 2011 IP-NEIGHBOUR(8)