IP-NEIGHBOUR(8)			     Linux		       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 STATE ] | proxy ADDR } [  dev DEV ] [  router ] [  use ] [
	       managed ] [  extern_learn ] [  extern_valid ]

       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.


	      extern_valid
		     this neigh entry was learned and determined to be valid
		     externally. The kernel will not remove or invalidate the
		     entry, but it can probe the entry and notify user space
		     when the entry becomes reachable. The kernel will return
		     the entry to stale state if it did not receive a
		     confirmation after probing the 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>

iproute2			  20 Dec 2011		       IP-NEIGHBOUR(8)