IP-NEIGHBOUR(8) Linux IP-NEIGHBOUR(8)NAMEip-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 bind‐
ings 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 proper‐
ties, 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
This command invalidates 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
This command displays neighbour tables.
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 val‐
ues 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 flushes neighbour tables, selecting entries to flush by
some criteria.
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 ALSOip(8)AUTHOR
Original Manpage by Michail Litvak <mci@owl.openwall.com>
iproute2 20 Dec 2011 IP-NEIGHBOUR(8)
