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 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.

       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 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>