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IPV6MON(8)		    System Manager's Manual		    IPV6MON(8)

NAME
       ipv6mon - IPv6 address monitoring daemon

SYNOPSIS
       ipv6mon [-c configfile] [-v] [-q] [-h]

DESCRIPTION
       ipv6mon is tool meant for monitoring IPv6 address usage on a local net-
       work. It	is particularly	useful in networks that	employ IPv6  Stateless
       Address	Auto-Configuration  (as	 opposed to DHCPv6), where address as-
       signment	is decentralized and there is no central server	 that  records
       which IPv6 addresses have been assigned to which	nodes during which pe-
       riod of time.

       ipv6mon employs a number	of techniques  to  determine  which  IPv6  ad-
       dresses	are  in	use on the local network, and active probing to	deter-
       mine whether such addresses remain active.

       ADDRESS DISCOVERY TECHNIQUES

       ipv6mon employs a number	of techniques techniques  to  discover	active
       IPv6 addresses:

	   + Active multicast probes
	   + Passive monitoring	of Duplicate Address Detection (DAD) traffic
	   + Address generation	heuristics

       Multicast probes

       ipv6mon	regularly sends	multicast probe	packets	to the all-nodes link-
       local multicast address (ff02::1), such that it can  discover  new  at-
       tached nodes. Two different types of probe packets are used:

	   + Regular ICMPv6 Echo Request packets
	   + ICMPv6 packets with an unsupported	IPv6 option of type 10xxxxxx

       Regular ICMPv6 Echo Request packets elicit ICMPv6 Echo Response packets
       from all	local nodes that normally respond  to  such  packets.  On  the
       other  hand,  ICMPv6  packets  including	 an unsupported	option of type
       10xxxxxx	elicit ICMPv6 Parameter	Problem	error messages,	and can	be ef-
       fective	to  discover  nodes  that  do not usually respond to multicast
       ICMPv6 echo requests.

       Both multicast probe packets are	sent with different Source  Addresses,
       such  that  they	elicit responses from different	addresses (as a	result
       of the default IPv6 Source Address selection policy).  Hence.  all  (or
       most) addresses of each node can	be discovered.

       Passive monitoring of Duplicate Address Detection (DAD) traffic

       ipv6mon	also  monitors IPv6 Duplicate Address Detection	(DAD) traffic,
       such that all newly configured addresses	are discovered as soon as pos-
       sible.

       Address generation heuristics

       Whenever	 an  active  address  is detected, heuristics are performed to
       discover	other addresses	in use by the same node.  Namely,  the	Inter-
       face-ID	of  the	 newly discovered address is used with all other local
       prefixes	to form	"candidate" addresses (addresses that might be in  use
       in the local network). Thus, it is possible for ipv6mon to discover ac-
       tive addresses even if they are not used	to send	traffic	on  the	 local
       network	(e.g., discover	traditional SLAAC addresses used by hosts that
       employ aPrivacy Addressesa).

OPTIONS
       Most of the operation parameters	of the ipv6mon tool can	be  configured
       by  the	system	administrator  through the corresponding configuration
       file. Some of them can be configured through command-line options.

       -c file,	--config-file file
	      This option specifies the	pathname of the	ipv6mon	 configuration
	      file, to be used instead of the default /etc/ipv6mon.conf.

       -q, --show-config
	      This  option  causes  ipv6mon to read the	configuration file and
	      output the different parameters that would result	from that con-
	      figuration.  When	 this option is	set, ipv6mon will exit immedi-
	      ately after the configuration parameters have  been  printed  on
	      standard output.

       -v, --verbose
	      This  option  causes  ipv6mon to read the	configuration file and
	      output the different parameters that would result	from that con-
	      figuration.  When	 this option is	set, ipv6mon will exit immedi-
	      ately after the configuration parameters have  been  printed  on
	      standard output.

       -h, --help
	      This  option  causes ipv6mon to print usage information on stan-
	      dard output.

FILES
       /etc/ipv6mon.conf
	      ipv6mon configuration file. See ipv6mon.conf(5) for further  de-
	      tails.

SEE ALSO
       ipv6mon.conf(5).

AUTHOR
       The  ipv6mon  tool  and the corresponding manual	pages were produced by
       Fernando	Gont <fgont@si6networks.com>.

COPYRIGHT
       Copyright (c) 2011-2012 Fernando	Gont.

       Permission is granted to	copy, distribute and/or	modify	this  document
       under  the  terms of the	GNU Free Documentation License,	Version	1.3 or
       any later version published by the Free Software	Foundation;  with  the
       Invariant  Sections being just "AUTHOR" and "COPYRIGHT",	with no	Front-
       Cover Texts, and	with no	Back-Cover Texts.  A copy of  the  license  is
       available at _http://www.gnu.org/licenses/fdl.html_.

								    IPV6MON(8)

NAME | SYNOPSIS | DESCRIPTION | OPTIONS | FILES | SEE ALSO | AUTHOR | COPYRIGHT

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