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 { 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 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 life-
		      time 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 commands 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 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 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 ALSO

       ip(8)

AUTHOR

       Original Manpage by Michail Litvak <mci@owl.openwall.com>

iproute2							    20 Dec 2011 						   IP-NEIGHBOUR(8)