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

     ndp -- control/diagnose IPv6 neighbor discovery protocol

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

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

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

	     Neighbor  IPv6 address of the neighbor.

	     Linklayer Address
		       Linklayer address of the	neighbor.  It could be
		       "(incomplete)" when the address is not available.

	     Netif     Network interface associated with the neighbor cache

	     Expire    The time	until expiry of	the entry.  The	entry could
		       become "permanent", in which case it will never expire.

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

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

	     Flags     Flags on	the neighbor cache entry, in a single letter.
		       They are: Router, proxy neighbor	advertisement ("p").
		       The field could be followed by a	decimal	number,	which
		       means the number	of NS probes the node has sent during
		       the current state.

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

     -c	     Erase all the NDP entries.

     -d	     Delete specified NDP entry.

     -f	     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 used as the default route when
	     there is no default router.  The interface	will be	used as	the

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

     -i	interface [expressions ...]
	     View ND information for the specified interface.  If additional
	     arguments expressions are given, ndp sets or clears the flags or
	     variables for the interface as specified in the expression.  Each
	     expression	should be separated by white spaces or tab characters.
	     Possible expressions are as follows.  Some	of the expressions can
	     begin with	the special character `-', which means the flag	speci-
	     fied in the expression should be cleared.	Note that you need --
	     before -foo in this case.

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

		     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.

		     Prefer addresses on the interface as candidates of	the
		     source address for	outgoing packets.  The default value
		     of	this flag is off.  For more details about the entire
		     algorithm of source address selection, see	the
		     IMPLEMENTATION file supplied with the KAME	kit.

		     Disable IPv6 operation on the interface.  When disabled,
		     the interface discards any	IPv6 packets received on or
		     being sent	to the interface.  In the sending case,	an er-
		     ror of ENETDOWN will be returned to the application.
		     This flag is typically set	automatically in the kernel as
		     a result of a certain failure of Duplicate	Address	Detec-
		     tion.  While the flag can be set or cleared by hand with
		     the ndp command, it is not	generally advisable to modify
		     this flag manually.

		     Specify the BaseReachbleTimer on the interface in mil-

		     Specify the RetransTimer on the interface in millisecond.

		     Specify the Cur Hop Limit on the interface.

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

     -p	     Show prefix list.

     -P	     Flush all the entries in the prefix list.

     -r	     Show default router list.

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

     -s	     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

     -t	     Print timestamp on	each entry, making it possible to merge	output
	     with tcpdump(1).  Most useful when	used with -A.

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


     The ndp utility first appeared in the WIDE	Hydrangea IPv6 protocol	stack

BSD				 May 17, 1998				   BSD


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