ndisc6(8)

1NDISC6(8)                   System Manager's Manual                  NDISC6(8)
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NAME

6       ndisc6 - ICMPv6 Neighbor Discovery tool
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SYNOPSIS

9       ndisc6 [-1mnqv] [-r attempts] [-w wait_ms] < IPv6 address> <iface>
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DESCRIPTON

13       NDisc6  is an Unix program which implements the ICMPv6 Neighbor Discov‐
14       ery in userland (it is normally done by the  kernel).  It  is  used  to
15       lookup the link-layer address (layer 2 address, MAC in the case of Eth‐
16       ernet) of any on-link IPv6 node.
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18       The IPv6 address of the node must be specified, as well as the network‐
19       ing interface on which to perform the lookup.
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OPTIONS

23       -1 or --single
24              Exit as soon as the first advertisement is received (default).
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27       -h or --help
28              Display some help and exit.
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31       -m or --multiple
32              Wait  for  possible  duplicate  advertisements  and print all of
33              them.
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36       -n or --numeric
37              If the first parameter is not a valid IPv6 address, do  not  try
38              to resolve it as a DNS hostname.
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41       -q or --quiet
42              Only  display  link-layer  address.  Display  nothing in case of
43              failure.  That is mostly useful when calling the program from  a
44              shell script.
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47       -r attempts or --retry attempts
48              Send  ICMPv6 Neighbor Discovery that many times until a reply is
49              received, or abort. By default, ndisc6 will try 3  times  before
50              aborting  (MAX_MULTICAST_SOLICIT  and  MAX_UNICAST_SOLICIT  from
51              RFC2461).
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54       -V or --version
55              Display program version and license and exit.
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58       -v or --verbose
59              Display verbose information. That is the default.
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62       -w wait_ms or --wait wait_ms
63              Wait wait_ms milliseconds for a response  before  retrying.   By
64              default,   ndisc6   waits   1   second   between  each  attempts
65              (RETRANS_TIMER from RFC2461).
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DIAGNOSTICS

69       If you get no response while you know the remote host is up, it is most
70       likely  that  it  is not on-link, that is to say, you must cross one or
71       more routers to reach it. By design, IPv6 nodes ignore ICMPv6  Neighbor
72       Discovery packets received from nodes not on the same link (i.e. Ether‐
73       net segment), for the sake of security. Technically, that  is  done  by
74       ensuring that the Hop limit (TTL) is 255.
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76       Note  that  you cannot use ndisc6 to lookup the local host's link-layer
77       address.
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SECURITY

81       ndisc6 should be setuid root to allow use by non privileged  users.  It
82       will  drop  its  root  privileges before any attempt is made to send or
83       receive data from the network to reduce the possible impact of a  secu‐
84       rity vulnerability.
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AUTHOR

92       Rémi Denis-Courmont <remi at remlab dot net>
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94       $Id: ndisc6.8 658 2010-10-31 20:56:30Z remi $
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96       http://www.remlab.net/ndisc6/
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100ndisc6      $Date: 2010-10-31 22:56:30 +0200 (dim. 31 oct. 2010) $   NDISC6(8)