draft-ietf-v6ops-addr-select-ps-00.txt		draft-ietf-v6ops-addr-select-ps-01.txt
	IPv6 Operations Working Group A. Matsumoto		IPv6 Operations Working Group A. Matsumoto
	Internet-Draft T. Fujisaki		Internet-Draft T. Fujisaki
	Intended status: Standards Track NTT		Intended status: Informational NTT
	Expires: May 14, 2007 R. Hiromi		Expires: October 7, 2007 R. Hiromi
	K. Kanayama		K. Kanayama
	Intec Netcore		Intec Netcore
	November 10, 2006		April 5, 2007
	Problem Statement of Default Address Selection in Multi-prefix		Problem Statement of Default Address Selection in Multi-prefix
	Environment: Operational Issues of RFC3484 Default Rules		Environment: Operational Issues of RFC3484 Default Rules
	draft-ietf-v6ops-addr-select-ps-00.txt		draft-ietf-v6ops-addr-select-ps-01.txt
	Status of this Memo		Status of this Memo
	By submitting this Internet-Draft, each author represents that any		By submitting this Internet-Draft, each author represents that any
	applicable patent or other IPR claims of which he or she is aware		applicable patent or other IPR claims of which he or she is aware
	have been or will be disclosed, and any of which he or she becomes		have been or will be disclosed, and any of which he or she becomes
	aware will be disclosed, in accordance with Section 6 of BCP 79.		aware will be disclosed, in accordance with Section 6 of BCP 79.
	Internet-Drafts are working documents of the Internet Engineering		Internet-Drafts are working documents of the Internet Engineering
	Task Force (IETF), its areas, and its working groups. Note that		Task Force (IETF), its areas, and its working groups. Note that
	skipping to change at page 1, line 38		skipping to change at page 1, line 38
	and may be updated, replaced, or obsoleted by other documents at any		and may be updated, replaced, or obsoleted by other documents at any
	time. It is inappropriate to use Internet-Drafts as reference		time. It is inappropriate to use Internet-Drafts as reference
	material or to cite them other than as "work in progress."		material or to cite them other than as "work in progress."
	The list of current Internet-Drafts can be accessed at		The list of current Internet-Drafts can be accessed at
	http://www.ietf.org/ietf/1id-abstracts.txt.		http://www.ietf.org/ietf/1id-abstracts.txt.
	The list of Internet-Draft Shadow Directories can be accessed at		The list of Internet-Draft Shadow Directories can be accessed at
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	This Internet-Draft will expire on May 14, 2007.		This Internet-Draft will expire on October 7, 2007.
	Copyright Notice		Copyright Notice
	Copyright (C) The Internet Society (2006).		Copyright (C) The IETF Trust (2007).
	Abstract		Abstract
	One physical network can carry multiple logical networks. Moreover,		One physical network can carry multiple logical networks. Moreover,
	we can use multiple physical networks at the same time in a host. In		we can use multiple physical networks at the same time in a host. In
	that environment, end-hosts might have multiple IP addresses and be		that environment, end-hosts might have multiple IP addresses and be
	required to use them selectively. Without an appropriate source/		required to use them selectively. Without an appropriate source/
	destination address selection mechanism, the host will experience		destination address selection mechanism, the host will experience
	some trouble in the communication. RFC 3484 defines both the source		some trouble in the communication. RFC 3484 defines both the source
	and destination address selection algorithms, but the multi-prefix		and destination address selection algorithms, but the multi-prefix
	skipping to change at page 2, line 20		skipping to change at page 2, line 20
	networks.		networks.
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
	1.1. Scope of this document . . . . . . . . . . . . . . . . . . 3		1.1. Scope of this document . . . . . . . . . . . . . . . . . . 3
	2. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 3		2. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 3
	2.1. Source Address Selection . . . . . . . . . . . . . . . . . 3		2.1. Source Address Selection . . . . . . . . . . . . . . . . . 3
	2.1.1. Multiple Routers on Single Interface . . . . . . . . . 4		2.1.1. Multiple Routers on Single Interface . . . . . . . . . 4
	2.1.2. Ingress Filtering Problem . . . . . . . . . . . . . . 5		2.1.2. Ingress Filtering Problem . . . . . . . . . . . . . . 5
	2.1.3. Half-Closed Network Problem . . . . . . . . . . . . . 6		2.1.3. Half-Closed Network Problem . . . . . . . . . . . . . 5
	2.1.4. Combined Use of Global and ULA . . . . . . . . . . . . 7		2.1.4. Combined Use of Global and ULA . . . . . . . . . . . . 7
	2.1.5. Site Renumbering . . . . . . . . . . . . . . . . . . . 8		2.1.5. Site Renumbering . . . . . . . . . . . . . . . . . . . 7
	2.1.6. Multicast Source Address Selection . . . . . . . . . . 8		2.1.6. Multicast Source Address Selection . . . . . . . . . . 8
	2.1.7. Temporary Address Selection . . . . . . . . . . . . . 8		2.1.7. Temporary Address Selection . . . . . . . . . . . . . 8
	2.2. Destination Address Selection . . . . . . . . . . . . . . 9		2.2. Destination Address Selection . . . . . . . . . . . . . . 8
	2.2.1. IPv4 or IPv6 prioritization . . . . . . . . . . . . . 9		2.2.1. IPv4 or IPv6 prioritization . . . . . . . . . . . . . 8
	2.2.2. ULA and IPv4 dual-stack environment . . . . . . . . . 10		2.2.2. ULA and IPv4 dual-stack environment . . . . . . . . . 9
	2.2.3. ULA or Global Prioritization . . . . . . . . . . . . . 10		2.2.3. ULA or Global Prioritization . . . . . . . . . . . . . 10
	3. Solutions . . . . . . . . . . . . . . . . . . . . . . . . . . 11		3. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . 11
	3.1. More Specific Routes (RFC 4191) . . . . . . . . . . . . . 11		4. Security Considerations . . . . . . . . . . . . . . . . . . . 11
	3.2. Policy Table Manipulation . . . . . . . . . . . . . . . . 11		5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
	3.3. Revising RFC 3484 . . . . . . . . . . . . . . . . . . . . 12		6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 12
	4. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . 12		6.1. Normative References . . . . . . . . . . . . . . . . . . . 12
	5. Security Considerations . . . . . . . . . . . . . . . . . . . 12		6.2. Informative References . . . . . . . . . . . . . . . . . . 12
	6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12		Appendix A. Appendix. Revision History . . . . . . . . . . . . . 12
	7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 12		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 12
	7.1. Normative References . . . . . . . . . . . . . . . . . . . 12		Intellectual Property and Copyright Statements . . . . . . . . . . 14
	7.2. Informative References . . . . . . . . . . . . . . . . . . 13
	Appendix A. Appendix. Revision History . . . . . . . . . . . . . 13
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 13
	Intellectual Property and Copyright Statements . . . . . . . . . . 15
	1. Introduction		1. Introduction
	One physical network can carry multiple logical networks. In that		One physical network can carry multiple logical networks. In that
	case, an end-host has multiple IP addresses. In the IPv4-IPv6 dual		case, an end-host has multiple IP addresses. In the IPv4-IPv6 dual
	stack environment or in a site connected to both ULA [RFC4193] and		stack environment or in a site connected to both ULA [RFC4193] and
	Global scope networks, an end-host has multiple IP addresses. These		Global scope networks, an end-host has multiple IP addresses. These
	are examples of the networks that we focus on in this document. In		are examples of the networks that we focus on in this document. In
	such an environment, an end-host will encounter some communication		such an environment, an end-host will encounter some communication
	trouble.		trouble.
	skipping to change at page 4, line 11		skipping to change at page 4, line 11
	2. Problem Statement		2. Problem Statement
	2.1. Source Address Selection		2.1. Source Address Selection
	2.1.1. Multiple Routers on Single Interface		2.1.1. Multiple Routers on Single Interface
	==================		==================
	| Internet |		| Internet |
	==================		==================
	| |		| |
	2001:db8::/32 | | 3ffe:1800::/32		2001:db8:1000::/36 | | 2001:db8:8000::/36
	+----+-+ +-+----+		+----+-+ +-+----+
	| ISP1 | | ISP2 |		| ISP1 | | ISP2 |
	+----+-+ +-+----+		+----+-+ +-+----+
	| |		| |
	2001:db8:a::/48 | | 3ffe:1800:a::/48		2001:db8:1000:::/48 | | 2001:db8:8000::/48
	+------+---+ +----+-----+		+------+---+ +----+-----+
	| Gateway1 | | Gateway2 |		| Gateway1 | | Gateway2 |
	+--------+-+ +-+--------+		+--------+-+ +-+--------+
	| |		| |
	2001:db8:a:1::/64 | | 3ffe:1800:a:1::/64		2001:db8:1000:1::/64 | | 2001:db8:8000:1::/64
	| |		| |
	-----+-+-----+------		-----+-+-----+------
	|		|
	+-+----+ 2001:db8:a:1:EUI64		+-+----+ 2001:db8:1000:1::EUI64
	| Host | 3ffe:1800:a:1:EUI64		| Host | 2001:db8:8000:1::EUI64
	+------+		+------+
	[Fig. 1]		[Fig. 1]
	Generally speaking, there is no interaction between next-hop		Generally speaking, there is no interaction between next-hop
	determination and address selection. In this example, when Host		determination and address selection. In this example, when Host
	sends a packet via Gateway1, the Host does not necessarily choose the		sends a packet via Gateway1, the Host does not necessarily choose the
	address 2001:db8:a:1::EUI64 given by Gateway1 as the source address.		address 2001:db8:1000:1::EUI64 given by Gateway1 as the source
	This causes the same problem as described in the next section		address. This causes the same problem as described in the next
	'Ingress Filtering Problem'.		section 'Ingress Filtering Problem'.
	To solve this case, one approach is to configure correctly both the
	routing configuration and address selection policy at Host. You can
	use RFC 4191 [RFC4191] to deliver routing information to hosts.
	Another approach is to configure the gateways to make use of packet
	redirection between the gateways.
	2.1.2. Ingress Filtering Problem		2.1.2. Ingress Filtering Problem
	==================		==================
	| Internet |		| Internet |
	==================		==================
	| |		| |
	2001:db8::/32 | | 3ffe:1800::/32		2001:db8:1000::/36 | | 2001:db8:8000::/36
	+----+-+ +-+----+		+----+-+ +-+----+
	| ISP1 | | ISP2 |		| ISP1 | | ISP2 |
	+----+-+ +-+----+		+----+-+ +-+----+
	| |		| |
	2001:db8:a::/48 | | 3ffe:1800:a::/48		2001:db8:1000:::/48 | | 2001:db8:8000::/48
	++-------++		++-------++
	| Gateway |		| Gateway |
	+----+----+		+----+----+
	| 2001:db8:a:1::/64		| 2001:db8:1000:1::/64
	| 3ffe:1800:a:1::/64		| 2001:db8:8000:1::/64
	------+---+----------		------+---+----------
	|		|
	+-+----+ 2001:db8:a:1:EUI64		+-+----+ 2001:db8:1000:1::EUI64
	| Host | 3ffe:1800:a:1:EUI64		| Host | 2001:db8:8000:1::EUI64
	+------+		+------+
	[Fig. 2]		[Fig. 2]
	When a relatively small site, which we call a "customer network", is		When a relatively small site, which we call a "customer network", is
	attached to two upstream ISPs, each ISP delegates a network address		attached to two upstream ISPs, each ISP delegates a network address
	block, which is usually /48, and a host has multiple IPv6 addresses.		block, which is usually /48, and a host has multiple IPv6 addresses.
	When the source address of an outgoing packet is not the one that is		When the source address of an outgoing packet is not the one that is
	delegated by an upstream ISP, there is a possibility that the packet		delegated by an upstream ISP, there is a possibility that the packet
	will be dropped at the ISP by its Ingress Filter. Ingress		will be dropped at the ISP by its Ingress Filter. Ingress
	filtering(uRPF: unicast Reverse Path Forwarding) is becoming more and		filtering(uRPF: unicast Reverse Path Forwarding) is becoming more and
	more popular among ISPs in order to mitigate the damage of DoS		more popular among ISPs in order to mitigate the damage of DoS
	attacks.		attacks.
	In this example, when the Gateway chooses the default route to ISP2		In this example, when the Gateway chooses the default route to ISP2
	and the Host chooses 2001:db8:a:1::EUI64 as the source address for		and the Host chooses 2001:db8:1000:1::EUI64 as the source address for
	packets sent to a host(2001:fa8::1) somewhere in the Internet, the		packets sent to a host(2001:db8:2000::1) somewhere in the Internet,
	packets may be dropped at ISP2 because of Ingress Filtering.		the packets may be dropped at ISP2 because of Ingress Filtering.
	One possible solution for this problem is to adopt source-address-
	based routing at the customer site's gateway, but this manner of
	routing is not very popular at the moment.
	2.1.3. Half-Closed Network Problem		2.1.3. Half-Closed Network Problem
	You can see a second typical source address selection problem in a		You can see a second typical source address selection problem in a
	multihome site with global-closed mixed connectivity like the figure		multihome site with global-closed mixed connectivity like the figure
	below. In this case, Host-A is in a multihomed network and has two		below. In this case, Host-A is in a multihomed network and has two
	IPv6 addresses, one delegated from each of the upstream ISPs. Note		IPv6 addresses, one delegated from each of the upstream ISPs. Note
	that ISP2 is a closed network and does not have connectivity to the		that ISP2 is a closed network and does not have connectivity to the
	Internet.		Internet.
	+--------+		+--------+
	| Host-C | 3ffe:503:c:1:EUI64		| Host-C | 2001:db8:a000::1
	+-----+--+		+-----+--+
	|		|
	============== +--------+		============== +--------+
	| Internet | | Host-B | 3ffe:1800::EUI64		| Internet | | Host-B | 2001:db8:8000::1
	============== +--------+		============== +--------+
	| |		| |
	2001:db8::/32 | | 3ffe:1800::/32		2001:db8:1000:/36 | | 2001:db8:8000::/36
	+----+-+ +-+---++		+----+-+ +-+---++
	| ISP1 | | ISP2 | (Closed Network/VPN tunnel)		| ISP1 | | ISP2 | (Closed Network/VPN tunnel)
	+----+-+ +-+----+		+----+-+ +-+----+
	| |		| |
	2001:db8:a::/48 | | 3ffe:1800:a::/48		2001:db8:1000:/48 | | 2001:db8:8000::/48
	++-------++		++-------++
	| Gateway |		| Gateway |
	+----+----+		+----+----+
	| 2001:db8:a:1::/64		| 2001:db8:1000:1::/64
	| 3ffe:1800:a:1::/64		| 2001:db8:8000:1::/64
	------+---+----------		------+---+----------
	|		|
	+--+-----+ 2001:db8:a:1:EUI64		+--+-----+ 2001:db8:1000:1::EUI64
	| Host-A | 3ffe:1800:a:1:EUI64		| Host-A | 2001:db8:8000:1::EUI64
	+--------+		+--------+
	[Fig. 3]		[Fig. 3]
	You don't need two physical network connection here. The connection		You don't need two physical network connection here. The connection
	from Gateway to ISP2 can be a logical link over ISP1 and the		from Gateway to ISP2 can be a logical link over ISP1 and the
	Internet.		Internet.
	When Host-A starts the connection to Host-B in ISP2, the source		When Host-A starts the connection to Host-B in ISP2, the source
	address of a sending packet will be the one delegated from ISP2, that		address of a sending packet will be the one delegated from ISP2, that
	is 3ffe:1800:a:1:EUI64, because of rule 8 (longest matching prefix)		is 2001:db8:8000:1::EUI64, because of rule 8 (longest matching
	in RFC 3484.		prefix) in RFC 3484.
	Host-C is located somewhere in the Internet and has an IPv6 address		Host-C is located somewhere in the Internet and has an IPv6 address
	3ffe:503:c:1:EUI64. When Host-A sends a packet to Host-C, the		2001:db8:a000::1. When Host-A sends a packet to Host-C, the longest
	longest matching algorithm chooses 3ffe:1800:a:1:EUI64 for the source		matching algorithm chooses 2001:db8:8000:1::EUI64 for the source
	address. In this case, the packet goes through ISP1 and may be		address. In this case, the packet goes through ISP1 and may be
	filtered by ISP1's ingress filter. Even if the packet is fortunately		filtered by ISP1's ingress filter. Even if the packet is fortunately
	not filtered by ISP1, a return packet from Host-C cannot possibly be		not filtered by ISP1, a return packet from Host-C cannot possibly be
	delivered to Host-A because the return packet is destined for 3ffe:		delivered to Host-A because the return packet is destined for 2001:
	1800:a:1:EUI64, which is closed from the Internet.		db8:8000:1::EUI64, which is closed from the Internet.
	In this case, source-address-based routing alone described in the		What is important is that each host chooses a correct source address
	previous section does not solve the problem. What is important is		for a given destination address as far as NAT does not exist in the
	that each host chooses a correct source address for a given		IPv6 world.
	destination address as far as NAT does not exist in the IPv6 world.
	2.1.4. Combined Use of Global and ULA		2.1.4. Combined Use of Global and ULA
	============		============
	| Internet |		| Internet |
	============		============
	|		|
	|		|
	+----+----+		+----+----+
	| ISP |		| ISP |
	+----+----+		+----+----+
	|		|
	2001:db8:a::/48 |		2001:db8:a::/48 |
	+----+----+		+----+----+
	| Gateway |		| Gateway |
	+-+-----+-+		+-+-----+-+
	| | 2001:db8:a:100::/64		| | 2001:db8:a:100::/64
	fd01:2:3:200:/64 | | fd01:2:3:100:/64		fd01:2:3:200:/64 | | fd01:2:3:100:/64
	-----+--+- -+--+----		-----+--+- -+--+----
	| |		| |
	fd01:2:3:200:EUI64 | | 2001:db8:a:100:EUI64		fd01:2:3:200::EUI64 | | 2001:db8:a:100::EUI64
	+----+----+ +-+----+ fd01:2:3:100:EUI64		+----+----+ +-+----+ fd01:2:3:100::EUI64
	| Printer | | Host |		| Printer | | Host |
	+---------+ +------+		+---------+ +------+
	[Fig. 4]		[Fig. 4]
	As NAP [I-D.ietf-v6ops-nap] describes, using ULA may be beneficial in		As NAP [I-D.ietf-v6ops-nap] describes, using ULA may be beneficial in
	some scenarios. If ULA is used for internal communication, packets		some scenarios. If ULA is used for internal communication, packets
	with ULA addresses need to be filtered at Gateway.		with ULA addresses need to be filtered at Gateway.
	There is no serious problem related to address selection in this		There is no serious problem related to address selection in this
	skipping to change at page 10, line 19		skipping to change at page 10, line 9
	Internet connectivity, and the enterprise wants to provide site-local		Internet connectivity, and the enterprise wants to provide site-local
	IPv6 connectivity, ULA is the best choice for site-local IPv6		IPv6 connectivity, ULA is the best choice for site-local IPv6
	connectivity. Each employee host will have both an IPv4 global or		connectivity. Each employee host will have both an IPv4 global or
	private address and a ULA. Here, when this host tries to connect to		private address and a ULA. Here, when this host tries to connect to
	Host-C that has registered both A and AAAA records in the DNS, the		Host-C that has registered both A and AAAA records in the DNS, the
	host will choose AAAA as the destination address and ULA for the		host will choose AAAA as the destination address and ULA for the
	source address. This will clearly result in a connection failure.		source address. This will clearly result in a connection failure.
	+--------+		+--------+
	| Host-C | AAAA = 2001:db8::80		| Host-C | AAAA = 2001:db8::80
	+-----+--+ A = 192.47.163.1		+-----+--+ A = 192.0.2.1
	|		|
	============		============
	| Internet |		| Internet |
	============		============
	| no IPv6 connectivity		| no IPv6 connectivity
	+----+----+		+----+----+
	| Gateway |		| Gateway |
	+----+----+		+----+----+
	|		|
	| fd01:2:3::/48 (ULA)		| fd01:2:3::/48 (ULA)
	| 192.0.2.0/24		| 192.0.2.128/25
	++--------+		++--------+
	| Router |		| Router |
	+----+----+		+----+----+
	| fd01:2:3:4::/64 (ULA)		| fd01:2:3:4::/64 (ULA)
	| 192.0.2.240/28		| 192.0.2.240/28
	------+---+----------		------+---+----------
	|		|
	+-+----+ fd01:2:3:4::100 (ULA)		+-+----+ fd01:2:3:4::100 (ULA)
	| Host | 192.0.2.245		| Host | 192.0.2.245
	+------+		+------+
	skipping to change at page 10, line 52		skipping to change at page 10, line 42
	[Fig. 7]		[Fig. 7]
	2.2.3. ULA or Global Prioritization		2.2.3. ULA or Global Prioritization
	It is very common to differentiate services by the client's source		It is very common to differentiate services by the client's source
	address. IP-address-based authentication is an extreme example of		address. IP-address-based authentication is an extreme example of
	this. Another typical example is a web service that has pages for		this. Another typical example is a web service that has pages for
	the public and internal pages for employees or involved parties. Yet		the public and internal pages for employees or involved parties. Yet
	another example is DNS zone splitting.		another example is DNS zone splitting.
	However, ULA and IPv6 global address both have global scope, and RFC		However, ULA and IPv6 global address both have global scope, and
	3484 default rules do not specify which address should be given		RFC3484 default rules do not specify which address should be given
	priority. This point makes IPv6 implementation of address-based		priority. This point makes IPv6 implementation of address-based
	service differentiation a bit harder.		service differentiation a bit harder.
	+------+		+------+
	| Host |		| Host |
	+-+--|-+		+-+--|-+
	| |		| |
	===========|==		===========|==
	| Internet | |		| Internet | |
	===========|==		===========|==
	skipping to change at page 11, line 27		skipping to change at page 11, line 24
	+----+-+ +-->+------+		+----+-+ +-->+------+
	| ISP +------+ DNS | 2001:db8:a::80		| ISP +------+ DNS | 2001:db8:a::80
	+----+-+ +-->+------+ fc12:3456:789a::80		+----+-+ +-->+------+ fc12:3456:789a::80
	| |		| |
	2001:db8:a::/48 | |		2001:db8:a::/48 | |
	fc12:3456:789a::/48 | |		fc12:3456:789a::/48 | |
	+----+----|+		+----+----|+
	| Gateway ||		| Gateway ||
	+---+-----|+		+---+-----|+
	| | 2001:db8:a:100::/64		| | 2001:db8:a:100::/64
	| | fc12:3456:789a:100:/64		| | fc12:3456:789a:100::/64
	--+-+---|-----		--+-+---|-----
	| |		| |
	+-+---|+ 2001:db8:a:100:EUI64		+-+---|+ 2001:db8:a:100::EUI64
	| Host | fc12:3456:789a:100:EUI64		| Host | fc12:3456:789a:100::EUI64
	+------+		+------+
	[Fig. 7]		[Fig. 7]
	3. Solutions		3. Conclusion
	3.1. More Specific Routes (RFC 4191)
	This method enables network administrator to distribute routing
	information to end-hosts. It can solve only two problems in this
	document, that is 2.1.1, 2.2.2. Routing information doesn't
	determine the source address when multiple addresses are attached to
	the outgoing network interface. So, it cannot be used for every
	cases here.
	3.2. Policy Table Manipulation
	Almost all the problem cases raised in this document can be solved by
	configuring the policy table at end-hosts. The problem for a site-
	administrator is that he does not have the means to deliver policies
	to end-hosts. Therefore, we proposed a method for policy
	distribution in the form of DHCPv6 option
	[I-D.fujisaki-dhc-addr-select-opt]. The usage of this mechanisim is
	illustrated in another I-D [I-D.arifumi-ipv6-policy-dist].
	3.3. Revising RFC 3484
	Revising address selection rules defined in RFC 3484 in another idea.
	These problems are, however, too network-environment-specific, so
	it's not easy to have all-purpose rule set.
	4. Conclusion
	We have covered problems related to destination or source address		We have covered problems related to destination or source address
	selection. These problems have their roots in the situation where		selection. These problems have their roots in the situation where
	end-hosts have multiple IP addresses. In this situation, every end-		end-hosts have multiple IP addresses. In this situation, every end-
	host must choose an appropriate destination and source address, which		host must choose an appropriate destination and source address, which
	cannot be achieved only by routers.		cannot be achieved only by routers.
	It should be noted that end-hosts must be informed about routing		It should be noted that end-hosts must be informed about routing
	policies of their upstream networks for appropriate address		policies of their upstream networks for appropriate address
	selection. A site administrator must consider every possible address		selection. A site administrator must consider every possible address
	false-selection problem and take countermeasures beforehand.		false-selection problem and take countermeasures beforehand.
	5. Security Considerations		4. Security Considerations
	Address false-selection can lead to serious security problem, such as		Address false-selection can lead to serious security problem, such as
	session hijack. However, it should be noted that address selection		session hijack. However, it should be noted that address selection
	is eventually up to end-hosts. We have no means to enforce one		is eventually up to end-hosts. We have no means to enforce one
	specific address selection policy to every end-host. So, a network		specific address selection policy to every end-host. So, a network
	administrator has to take countermeasures for unexpected address		administrator has to take countermeasures for unexpected address
	selection.		selection.
	6. IANA Considerations		5. IANA Considerations
	This document has no actions for IANA.		This document has no actions for IANA.
	7. References		6. References
	7.1. Normative References		6.1. Normative References
	[RFC3484] Draves, R., "Default Address Selection for Internet		[RFC3484] Draves, R., "Default Address Selection for Internet
	Protocol version 6 (IPv6)", RFC 3484, February 2003.		Protocol version 6 (IPv6)", RFC 3484, February 2003.
	[RFC4193] Hinden, R. and B. Haberman, "Unique Local IPv6 Unicast		[RFC4193] Hinden, R. and B. Haberman, "Unique Local IPv6 Unicast
	Addresses", RFC 4193, October 2005.		Addresses", RFC 4193, October 2005.
	7.2. Informative References		6.2. Informative References
	[I-D.arifumi-ipv6-policy-dist]
	Matsumoto, A., "Practical Usages of Address Selection
	Policy Distribution", draft-arifumi-ipv6-policy-dist-01
	(work in progress), June 2006.
	[I-D.fujisaki-dhc-addr-select-opt]
	Fujisaki, T., "Distributing Default Address Selection
	Policy using DHCPv6",
	draft-fujisaki-dhc-addr-select-opt-02 (work in progress),
	June 2006.
	[I-D.ietf-v6ops-nap]		[I-D.ietf-v6ops-nap]
	Velde, G., "Network Architecture Protection for IPv6",		Velde, G., "Local Network Protection for IPv6",
	draft-ietf-v6ops-nap-04 (work in progress), October 2006.		draft-ietf-v6ops-nap-06 (work in progress), January 2007.
	[RFC3041] Narten, T. and R. Draves, "Privacy Extensions for		[RFC3041] Narten, T. and R. Draves, "Privacy Extensions for
	Stateless Address Autoconfiguration in IPv6", RFC 3041,		Stateless Address Autoconfiguration in IPv6", RFC 3041,
	January 2001.		January 2001.
	[RFC4191] Draves, R. and D. Thaler, "Default Router Preferences and
	More-Specific Routes", RFC 4191, November 2005.
	[RFC4192] Baker, F., Lear, E., and R. Droms, "Procedures for		[RFC4192] Baker, F., Lear, E., and R. Droms, "Procedures for
	Renumbering an IPv6 Network without a Flag Day", RFC 4192,		Renumbering an IPv6 Network without a Flag Day", RFC 4192,
	September 2005.		September 2005.
	[RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing		[RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing
	Architecture", RFC 4291, February 2006.		Architecture", RFC 4291, February 2006.
	Appendix A. Appendix. Revision History		Appendix A. Appendix. Revision History
	01:		01:
	Authors' addresses corrected.		IP addresse notations changed to docmentation address.
	Solutions section added.		Descriptoin of solutions deleted.
	Security Considerations section fully rewritten.
	Some editorial changes.
	Authors' Addresses		Authors' Addresses
	Arifumi Matsumoto		Arifumi Matsumoto
	NTT PF Lab		NTT PF Lab
	Midori-Cho 3-9-11		Midori-Cho 3-9-11
	Musashino-shi, Tokyo 180-8585		Musashino-shi, Tokyo 180-8585
	Japan		Japan
	Phone: +81 422 59 3334		Phone: +81 422 59 3334
	Email: arifumi@nttv6.net		Email: arifumi@nttv6.net
	Tomohiro Fujisaki		Tomohiro Fujisaki
	NTT PF Lab		NTT PF Lab
	Midori-Cho 3-9-11		Midori-Cho 3-9-11
	Musashino-shi, Tokyo 180-8585		Musashino-shi, Tokyo 180-8585
	Japan		Japan
	Phone: +81 422 59 7351		Phone: +81 422 59 7351
	Email: fujisaki@syce.net		Email: fujisaki@nttv6.net
	Ruri Hiromi		Ruri Hiromi
	Intec Netcore, Inc.		Intec Netcore, Inc.
	Shinsuna 1-3-3		Shinsuna 1-3-3
	Koto-ku, Tokyo 136-0075		Koto-ku, Tokyo 136-0075
	Japan		Japan
	Phone: +81 3 5665 5069		Phone: +81 3 5665 5069
	Email: hiromi@inetcore.com		Email: hiromi@inetcore.com
	skipping to change at page 15, line 7		skipping to change at page 14, line 7
	Intec Netcore, Inc.		Intec Netcore, Inc.
	Shinsuna 1-3-3		Shinsuna 1-3-3
	Koto-ku, Tokyo 136-0075		Koto-ku, Tokyo 136-0075
	Japan		Japan
	Phone: +81 3 5665 5069		Phone: +81 3 5665 5069
	Email: kanayama@inetcore.com		Email: kanayama@inetcore.com
	Full Copyright Statement		Full Copyright Statement
	Copyright (C) The Internet Society (2006).		Copyright (C) The IETF Trust (2007).
	This document is subject to the rights, licenses and restrictions		This document is subject to the rights, licenses and restrictions
	contained in BCP 78, and except as set forth therein, the authors		contained in BCP 78, and except as set forth therein, the authors
	retain all their rights.		retain all their rights.
	This document and the information contained herein are provided on an		This document and the information contained herein are provided on an
	"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS		"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
	OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET		OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND
	ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,		THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS
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	INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED		THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
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	Intellectual Property		Intellectual Property
	The IETF takes no position regarding the validity or scope of any		The IETF takes no position regarding the validity or scope of any
	Intellectual Property Rights or other rights that might be claimed to		Intellectual Property Rights or other rights that might be claimed to
	pertain to the implementation or use of the technology described in		pertain to the implementation or use of the technology described in
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