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NDISC6(8)		    System Manager's Manual		     NDISC6(8)

NAME
       ndisc6 -	ICMPv6 Neighbor	Discovery tool

SYNOPSIS
       ndisc6  [-1mnqv]	 [-r  attempts]	 [-s source_ip]	[-w wait_ms] <IPv6 ad-
       dress> <iface>

DESCRIPTON
       NDisc6 is an Unix program which implements the ICMPv6 Neighbor  Discov-
       ery  in	userland  (it  is  normally done by the	kernel). It is used to
       lookup the link-layer address (layer 2 address, MAC in the case of Eth-
       ernet) of any on-link IPv6 node.

       The IPv6	address	of the node must be specified, as well as the network-
       ing interface on	which to perform the lookup.

OPTIONS
       -1 or --single
	      Exit as soon as the first	advertisement is received (default).

       -h or --help
	      Display some help	and exit.

       -m or --multiple
	      Wait for possible	duplicate  advertisements  and	print  all  of
	      them.

       -n or --numeric
	      If  the  first parameter is not a	valid IPv6 address, do not try
	      to resolve it as a DNS hostname.

       -q or --quiet
	      Only display link-layer address.	Display	 nothing  in  case  of
	      failure.	 That is mostly	useful when calling the	program	from a
	      shell script.

       -r attempts or --retry attempts
	      Send ICMPv6 Neighbor Discovery that many times until a reply  is
	      received,	 or  abort. By default,	ndisc6 will try	3 times	before
	      aborting	(MAX_MULTICAST_SOLICIT	and  MAX_UNICAST_SOLICIT  from
	      RFC2461).

       -s source_ip or --source	source_ip
	      Specify the IPv6 address to be used as the source	for the	neigh-
	      bor solicitation packets.

       -V or --version
	      Display program version and license and exit.

       -v or --verbose
	      Display verbose information. That	is the default.

       -w wait_ms or --wait wait_ms
	      Wait wait_ms milliseconds	for a response	before	retrying.   By
	      default,	ndisc6	waits  1  second  between  each	 attempts (RE-
	      TRANS_TIMER from RFC2461).

       If ndisc6 does not receive any response after the specified  number  of
       attempts	 waiting for wait_ms milliseconds each time, it	will exit with
       code 2. On error, it exits with code 1.	Otherwise it exits  with  code
       0.  This	makes it possible to use the exit code to see if a host	is on-
       link or not.

DIAGNOSTICS
       If you get no response while you	know the remote	host is	up, it is most
       likely  that  it	 is not	on-link, that is to say, you must cross	one or
       more routers to reach it. By design, IPv6 nodes ignore ICMPv6  Neighbor
       Discovery packets received from nodes not on the	same link (i.e.	Ether-
       net segment), for the sake of security. Technically, that  is  done  by
       ensuring	that the Hop limit (TTL) is 255.

       Note  that  you cannot use ndisc6 to lookup the local host's link-layer
       address.

SECURITY
       ndisc6 should be	setuid root to allow use by non-privileged  users.  It
       will drop its root privileges before any	attempt	is made	to send	or re-
       ceive data from the network to reduce the possible impact of a security
       vulnerability.

SEE ALSO
       ping6(8), rdisc6(8), ipv6(7)

AUTHOR
       Remi Denis-Courmont <remi at remlab dot net>

       http://www.remlab.net/ndisc6/

ndisc6				    $Date$			     NDISC6(8)

NAME | SYNOPSIS | DESCRIPTON | OPTIONS | DIAGNOSTICS | SECURITY | SEE ALSO | AUTHOR

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