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NDISC6

NDISC6

Section: System Manager's Manual (8) Updated: $Date: 2007-08-08 18:09:36 +0300 (Wed, 08 Aug 2007) $
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NAME

ndisc6 - ICMPv6 Neighbor Discovery tool  

SYNOPSIS

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

 

DESCRIPTON

NDisc6 is an Unix program which implements the ICMPv6 Neighbor Discovery 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 Ethernet) of any on-link IPv6 node.

The IPv6 address of the node must be specified, as well as the networking 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).

-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 (RETRANS_TIMER from RFC2461).

 

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. Ethernet 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 receive data from the network to reduce the possible impact of a security vulnerability.

 

SEE ALSO

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

 

AUTHOR

R33mi Denis-Courmont <rdenis at simphalempin.com>

$Id: ndisc6.8 483 2007-08-08 15:09:36Z remi $

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


 

Index

NAME
SYNOPSIS
DESCRIPTON
OPTIONS
DIAGNOSTICS
SECURITY
SEE ALSO
AUTHOR

This document was created by man2html, using the manual pages.
Time: 22:02:02 GMT, April 16, 2011