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 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 ta-
       ble.

       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.  Particu-
              larly, 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)