NAME | SYNOPSIS | DESCRIPTION | EXAMPLES | SEE ALSO | AUTHOR | COLOPHON

IP-NEIGHBOUR(8)                     Linux                    IP-NEIGHBOUR(8)

NAME         top

       ip-neighbour - neighbour/arp tables management.

SYNOPSIS         top

       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         top

       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         top

       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         top

       ip(8)

AUTHOR         top

       Original Manpage by Michail Litvak <mci@owl.openwall.com>

COLOPHON         top

       This page is part of the iproute2 (utilities for controlling TCP/IP
       networking and traffic) project.  Information about the project can
       be found at 
       ⟨http://www.linuxfoundation.org/collaborate/workgroups/networking/iproute2⟩.
       If you have a bug report for this manual page, send it to
       netdev@vger.kernel.org, shemminger@osdl.org.  This page was obtained
       from the project's upstream Git repository 
       ⟨git://git.kernel.org/pub/scm/linux/kernel/git/shemminger/iproute2.git⟩
       on 2017-04-25.  If you discover any rendering problems in this HTML
       version of the page, or you believe there is a better or more up-to-
       date source for the page, or you have corrections or improvements to
       the information in this COLOPHON (which is not part of the original
       manual page), send a mail to man-pages@man7.org

iproute2                         20 Dec 2011                 IP-NEIGHBOUR(8)

Pages that refer to this page: ip(8)