NDP(8)                  OpenBSD System Manager's Manual                 NDP(8)

NAME
     ndp - control/diagnose IPv6 Neighbor Discovery Protocol (NDP)

SYNOPSIS
     ndp [-nrt] [-a | -c | -p] [-H | -P | -R] [-A wait] [-d hostname]
         [-f filename] [-I [interface | delete]] [-i interface [flag ...]]
         [-s nodename etheraddr [temp] [proxy]] [hostname]

DESCRIPTION
     The ndp command manipulates the address mapping table used by the Neigh-
     bor Discovery Protocol (NDP).

     -A wait
             Repeat -a (dump NDP entries) every wait seconds.

     -a      Dump the currently existing NDP entries.  The following informa-
             tion will be printed:

                Neighbor
                        The IPv6 address of the neighbor.

                Linklayer Address
                        The linklayer address of the neighbor.  If the address
                        is not available, it will be displayed as
                        ``(incomplete)''.

                Netif   The network interface associated with the neighbor
                        cache entry.

                Expire  The time until expiry of the entry.  If the entry is
                        marked ``permanent'', it will never expire.

                S       The state of the neighbor cache entry, as a single
                        letter:

                           D       Delay
                           I       Incomplete
                           N       Nostate
                           P       Probe
                           R       Reachable
                           S       Stale
                           W       Waitdelete
                           ?       Unknown state (should never happen).

                Flags   Flags on the neighbor cache entry, in a single letter.
                        They are: Router (`R') and proxy neighbor advertise-
                        ment (`p').  This field may be followed by a decimal
                        number, representing the number of NS probes the node
                        has sent during the current state.

     -c      Erase all the NDP entries.

     -d hostname
             Delete the specified NDP entry.

     -f filename
             Parse the file specified by filename.

     -H      Harmonize consistency between the routing table and the default
             router list; install the top entry of the list into the kernel
             routing table.

     -I      Shows the default interface used as the default route when there
             is no default router.

     -I interface
             Specifies the default interface to be used when there is no in-
             terface specified even though required.

     -I delete
             The current default interface will be deleted from the kernel.

     -i interface [flag ...]
             View ND information for the specified interface.  If additional
             arguments are given, ndp sets or clears the specified flags for
             the interface.  Each flag should be separated by whitespace or
             tab characters.  Possible flags are as follows.  All of the flags
             can begin with the special character `-', which means the flag
             should be cleared.  Note that -- would be needed before -foo in
             this case.

             nud     Turn on or off NUD (Neighbor Unreachability Detection) on
                     the interface.  NUD is usually turned on by default.

             accept_rtadv
                     Specify whether or not to accept Router Advertisement
                     messages received on the interface.  Note that the kernel
                     does not accept Router Advertisement messages unless the
                     net.inet6.ip6.accept_rtadv variable is non-0, even if the
                     flag is on.  This flag is set to 1 by default.  See
                     sysctl(8) and sysctl.conf(5) for further details on how
                     to set the net.inet6.ip6.accept_rtadv variable.

     -n      Do not try to resolve numeric addresses to hostnames.

     -P      Flush all the entries in the prefix list.

     -p      Show the prefix list.

     -R      Flush all the entries in the default router list.

     -r      Show the default router list.

     -s nodename etheraddr [temp] [proxy]
             Register an NDP entry for a node.  The entry will be permanent
             unless the word temp is given in the command.  If the word proxy
             is given, this system will act as a proxy NDP server, responding
             to requests for hostname even though the host address is not its
             own.

     -t      Print a timestamp on each entry, making it possible to merge out-
             put with tcpdump(8).  Most useful when used with -A.

     The ndp utility exits 0 on success, and >0 if an error occurs.

SEE ALSO
     ip6(4), sysctl.conf(5), arp(8), sysctl(8), tcpdump(8)

HISTORY
     The ndp command first appeared in the WIDE Hydrangea IPv6 protocol stack
     kit.

OpenBSD 4.7                      May 18, 2008                                2
