IP-NEIGHBOUR(8)           (20 Dec 2011)           IP-NEIGHBOUR(8)

     NAME
          ip-neighbour - neighbour/arp tables management.

     SYNOPSIS
          ip [ OPTIONS ] neigh  { COMMAND | help }

          ip neigh { add | del | ADDR [  lladdr LLADDR ] [  nud STATE
                  ] | proxy ADDR } [  dev DEV ] [  router ] [
                  extern_learn ]

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

          ip neigh get ADDR dev DEV

          STATE := { permanent | noarp | stale | incomplete | delay |
                  probe |

     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.

     Page 1                      iproute2            (printed 5/24/22)

     IP-NEIGHBOUR(8)           (20 Dec 2011)           IP-NEIGHBOUR(8)

               dev NAME
                    the interface to which this neighbour is attached.

               proxy
                    indicates whether we are proxying for this neigh-
                    bour entry

               router
                    indicates whether neighbour is a router

               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.

               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 Detec-
                    tion'.  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 reach-
                         ability 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

     Page 2                      iproute2            (printed 5/24/22)

     IP-NEIGHBOUR(8)           (20 Dec 2011)           IP-NEIGHBOUR(8)

                         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 suc-
                         cess, 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.

     Page 3                      iproute2            (printed 5/24/22)

     IP-NEIGHBOUR(8)           (20 Dec 2011)           IP-NEIGHBOUR(8)

               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 dif-
               ferences 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 ver-
               bose. 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 neigh-
                    bour 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.

     Page 4                      iproute2            (printed 5/24/22)

     IP-NEIGHBOUR(8)           (20 Dec 2011)           IP-NEIGHBOUR(8)

          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>

     Page 5                      iproute2            (printed 5/24/22)