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
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.
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.
