ip-neighbour

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 ] [ router ] [ extern_learn ]

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

       ip neigh get ADDR dev DEV

       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.


              proxy  indicates whether we are proxying for this neighbour 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 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.


       ip neigh get
              lookup a neighbour entry to a destination given a device


              proxy  indicates whether we should lookup a proxy neighbour 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.

       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>



iproute2                           20 Dec 2011                   IP-NEIGHBOUR(8)