ip-neighbour(8)
NAME
ip-neighbour - neighbour/arp tables management.
SYNOPSIS
ip [ OPTIONS ] neigh { COMMAND | help }
ip neigh { add | del | change | replace } { ADDR [ lladdr LLADDR ] [
nud { permanent | noarp | stale | reachable } ] | proxy ADDR }
[ dev DEV ]
ip neigh { show | flush } [ proxy ] [ to PREFIX ] [ dev DEV ] [ nud
STATE ]
DESCRIPTION
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 ARP table.
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
ones.
to ADDRESS (default)
the protocol address of the neighbour. It is either an
IPv4 or IPv6 address.
dev NAME
the interface to which this neighbour is attached.
lladdr LLADDRESS
the link layer address of the neighbour. LLADDRESS can
also be null.
nud NUD_STATE
the state of the neighbour entry. nud is an abbreviation
for 'Neighbour Unreachability Detection'. The state can
take one of the following values:
permanent
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.
reachable
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.
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 broadcast.
ip neighbour show
list neighbour entries
to ADDRESS (default)
the prefix selecting the neighbours to list.
dev NAME
only list the neighbours attached to this device.
proxy list neighbour proxies.
unused only list neighbours which are not currently in use.
nud NUD_STATE
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 neighbours.
EXAMPLES
ip neighbour
Shows the current neighbour table in kernel.
ip neigh flush dev eth0
Removes entries in the neighbour table on device eth0.
SEE ALSO
ip(8)
AUTHOR
Original Manpage by Michail Litvak <mci@owl.openwall.com>
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