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

              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.

              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 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)