Provided by: iproute2_6.10.0-2ubuntu1_amd64 
NAME
ip-neighbour - neighbour/arp tables management.
SYNOPSIS
ip [ OPTIONS ] neigh { COMMAND | help }
ip neigh { add | del | change | replace } { ADDR [ lladdr LLADDR ] [ nud STATE ] | proxy
ADDR } [ dev DEV ] [ router ] [ use ] [ managed ] [ extern_learn ]
ip neigh { show | flush } [ proxy ] [ to PREFIX ] [ dev DEV ] [ nud STATE ] [ vrf NAME ] [
nomaster ]
ip neigh get ADDR dev DEV
STATE := { permanent | noarp | stale | reachable | none | incomplete | delay | probe |
failed }
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.
proxy indicates whether we are proxying for this neighbour entry
router indicates whether neighbour is a router
use this neigh entry is in "use". This option can be used to indicate to the
kernel that a controller is using this dynamic entry. If the entry does not
exist, the kernel will resolve it. If it exists, an attempt to refresh the
neighbor entry will be triggered.
managed
this neigh entry is "managed". This option can be used to indicate to the
kernel that a controller is using this dynamic entry. In contrast to "use",
if the entry does not exist, the kernel will resolve it and periodically
attempt to auto-refresh the neighbor entry such that it remains in resolved
state when possible.
extern_learn
this neigh entry was learned externally. This option can be used to indicate
to the kernel that this is a controller learnt dynamic entry. Kernel will
not gc such an entry.
lladdr LLADDRESS
the link layer address of the neighbour. LLADDRESS can also be null.
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.
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.
incomplete
the neighbour entry has not (yet) been validated/resolved.
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 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.
vrf NAME
only list the neighbours for given VRF.
nomaster
only list neighbours attached to an interface with no master.
proxy list neighbour proxies.
unused only list neighbours which are not currently in use.
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.
ip neigh get
lookup a neighbour entry to a destination given a device
proxy indicates whether we should lookup a proxy neighbour entry
to ADDRESS (default)
the prefix selecting the neighbour to query.
dev NAME
get neighbour entry attached to this device.
EXAMPLES
ip neighbour
Shows the current neighbour table in kernel.
ip neigh flush dev eth0
Removes entries in the neighbour table on device eth0.
ip neigh get 10.0.1.10 dev eth0
Performs a neighbour lookup in the kernel and returns a neighbour entry.
SEE ALSO
ip(8)
AUTHOR
Original Manpage by Michail Litvak <mci@owl.openwall.com>