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
               ]

       ip neigh { show | flush } [ proxy ] [ to PREFIX ] [ dev DEV ] [ nud STATE ] [ vrf NAME ]

       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.

              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.

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)