< draft-ietf-ipv6-privacy-addrs-v2-04.txt		draft-ietf-ipv6-privacy-addrs-v2-05.txt >
	IPv6 Working Group T. Narten		IPv6 Working Group T. Narten
	Internet-Draft IBM Corporation		Internet-Draft IBM Corporation
	Expires: November 25, 2005 R. Draves		Obsoletes: 3041 (if approved) R. Draves
	Microsoft Research		Expires: February 2, 2007 Microsoft Research
	S. Krishnan		S. Krishnan
	Ericsson Research		Ericsson Research
	May 24, 2005		August 2006
	Privacy Extensions for Stateless Address Autoconfiguration in IPv6		Privacy Extensions for Stateless Address Autoconfiguration in IPv6
	draft-ietf-ipv6-privacy-addrs-v2-04		draft-ietf-ipv6-privacy-addrs-v2-05
	Status of this Memo		Status of this Memo
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	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.
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	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 37 ¶		skipping to change at page 1, line 37 ¶
	and may be updated, replaced, or obsoleted by other documents at any		and may be updated, replaced, or obsoleted by other documents at any
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	http://www.ietf.org/ietf/1id-abstracts.txt.		http://www.ietf.org/ietf/1id-abstracts.txt.
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	This Internet-Draft will expire on November 25, 2005.		This Internet-Draft will expire on February 2, 2007.
	Copyright Notice		Copyright Notice
	Copyright (C) The Internet Society (2005).		Copyright (C) The Internet Society (2006).
	Abstract		Abstract
	Nodes use IPv6 stateless address autoconfiguration to generate		Nodes use IPv6 stateless address autoconfiguration to generate
	addresses using a combination of locally available information and		addresses using a combination of locally available information and
	information advertised by routers. Addresses are formed by combining		information advertised by routers. Addresses are formed by combining
	network prefixes with an interface identifier. On interfaces that		network prefixes with an interface identifier. On interfaces that
	contain embedded IEEE Identifiers, the interface identifier is		contain embedded IEEE Identifiers, the interface identifier is
	typically derived from it. On other interface types, the interface		typically derived from it. On other interface types, the interface
	identifier is generated through other means, for example, via random		identifier is generated through other means, for example, via random
	skipping to change at page 2, line 20 ¶		skipping to change at page 2, line 20 ¶
	identifiers that change over time, even in cases where the interface		identifiers that change over time, even in cases where the interface
	contains an embedded IEEE identifier. Changing the interface		contains an embedded IEEE identifier. Changing the interface
	identifier (and the global scope addresses generated from it) over		identifier (and the global scope addresses generated from it) over
	time makes it more difficult for eavesdroppers and other information		time makes it more difficult for eavesdroppers and other information
	collectors to identify when different addresses used in different		collectors to identify when different addresses used in different
	transactions actually correspond to the same node.		transactions actually correspond to the same node.
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
	1.1 Conventions used in this document . . . . . . . . . . . . 4		1.1. Conventions used in this document . . . . . . . . . . . . 4
	1.2 Problem Statement . . . . . . . . . . . . . . . . . . . . 4		1.2. Problem Statement . . . . . . . . . . . . . . . . . . . . 4
	2. Background . . . . . . . . . . . . . . . . . . . . . . . . . . 5		2. Background . . . . . . . . . . . . . . . . . . . . . . . . . . 5
	2.1 Extended Use of the Same Identifier . . . . . . . . . . . 5		2.1. Extended Use of the Same Identifier . . . . . . . . . . . 5
	2.2 Address Usage in IPv4 Today . . . . . . . . . . . . . . . 6		2.2. Address Usage in IPv4 Today . . . . . . . . . . . . . . . 6
	2.3 The Concern With IPv6 Addresses . . . . . . . . . . . . . 7		2.3. The Concern With IPv6 Addresses . . . . . . . . . . . . . 7
	2.4 Possible Approaches . . . . . . . . . . . . . . . . . . . 8		2.4. Possible Approaches . . . . . . . . . . . . . . . . . . . 8
	3. Protocol Description . . . . . . . . . . . . . . . . . . . . . 10		3. Protocol Description . . . . . . . . . . . . . . . . . . . . . 10
	3.1 Assumptions . . . . . . . . . . . . . . . . . . . . . . . 10		3.1. Assumptions . . . . . . . . . . . . . . . . . . . . . . . 10
	3.2 Generation Of Randomized Interface Identifiers . . . . . . 12		3.2. Generation Of Randomized Interface Identifiers . . . . . . 12
	3.2.1 When Stable Storage Is Present . . . . . . . . . . . . 12		3.2.1. When Stable Storage Is Present . . . . . . . . . . . . 12
	3.2.2 In The Absence of Stable Storage . . . . . . . . . . . 13		3.2.2. In The Absence of Stable Storage . . . . . . . . . . . 13
	3.2.3 Alternate approaches . . . . . . . . . . . . . . . . . 14		3.2.3. Alternate approaches . . . . . . . . . . . . . . . . . 14
	3.3 Generating Temporary Addresses . . . . . . . . . . . . . . 14		3.3. Generating Temporary Addresses . . . . . . . . . . . . . . 14
	3.4 Expiration of Temporary Addresses . . . . . . . . . . . . 15		3.4. Expiration of Temporary Addresses . . . . . . . . . . . . 15
	3.5 Regeneration of Randomized Interface Identifiers . . . . . 16		3.5. Regeneration of Randomized Interface Identifiers . . . . . 16
	3.6 Deployment Considerations . . . . . . . . . . . . . . . . 17		3.6. Deployment Considerations . . . . . . . . . . . . . . . . 17
	4. Implications of Changing Interface Identifiers . . . . . . . . 19		4. Implications of Changing Interface Identifiers . . . . . . . . 19
	5. Defined Constants . . . . . . . . . . . . . . . . . . . . . . 20		5. Defined Constants . . . . . . . . . . . . . . . . . . . . . . 20
	6. Future Work . . . . . . . . . . . . . . . . . . . . . . . . . 21		6. Future Work . . . . . . . . . . . . . . . . . . . . . . . . . 21
	7. Significant Changes from RFC 3041 . . . . . . . . . . . . . . 22		7. Security Considerations . . . . . . . . . . . . . . . . . . . 22
	8. Changes from version 00 . . . . . . . . . . . . . . . . . . . 23		8. Significant Changes from RFC 3041 . . . . . . . . . . . . . . 23
	9. Changes from version 01 . . . . . . . . . . . . . . . . . . . 24		9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 24
	10. Changes from version 02 . . . . . . . . . . . . . . . . . . 25		10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 25
	11. Changes from version 03 . . . . . . . . . . . . . . . . . . 26		10.1. Normative References . . . . . . . . . . . . . . . . . . . 25
	12. Security Considerations . . . . . . . . . . . . . . . . . . 27		10.2. Informative References . . . . . . . . . . . . . . . . . . 25
	13. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 28		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 27
	14. References . . . . . . . . . . . . . . . . . . . . . . . . . 29		Intellectual Property and Copyright Statements . . . . . . . . . . 28
	14.1 Normative References . . . . . . . . . . . . . . . . . . . 29
	14.2 Informative References . . . . . . . . . . . . . . . . . . 29
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 30
	Intellectual Property and Copyright Statements . . . . . . . . 32
	1. Introduction		1. Introduction
	Stateless address autoconfiguration [ADDRCONF] defines how an IPv6		Stateless address autoconfiguration [ADDRCONF] defines how an IPv6
	node generates addresses without the need for a DHCPv6 server. Some		node generates addresses without the need for a DHCPv6 server. Some
	types of network interfaces come with an embedded IEEE Identifier		types of network interfaces come with an embedded IEEE Identifier
	(i.e., a link-layer MAC address), and in those cases stateless		(i.e., a link-layer MAC address), and in those cases stateless
	address autoconfiguration uses the IEEE identifier to generate a 64-		address autoconfiguration uses the IEEE identifier to generate a 64-
	bit interface identifier [ADDRARCH]. By design, the interface		bit interface identifier [ADDRARCH]. By design, the interface
	identifier is likely to be globally unique when generated in this		identifier is likely to be globally unique when generated in this
	skipping to change at page 4, line 5 ¶		skipping to change at page 4, line 5 ¶
	help mitigate those concerns for individual users and in environments		help mitigate those concerns for individual users and in environments
	where such concerns are significant. Section 2 provides background		where such concerns are significant. Section 2 provides background
	information on the issue. Section 3 describes a procedure for		information on the issue. Section 3 describes a procedure for
	generating alternate interface identifiers and global scope		generating alternate interface identifiers and global scope
	addresses. Section 4 discusses implications of changing interface		addresses. Section 4 discusses implications of changing interface
	identifiers. The term "global scope addresses" is used in this		identifiers. The term "global scope addresses" is used in this
	document to collectively refer to "Global unicast addresses" as		document to collectively refer to "Global unicast addresses" as
	defined in [ADDRARCH] and "Unique local addresses" as defined in		defined in [ADDRARCH] and "Unique local addresses" as defined in
	[ULA]		[ULA]
	1.1 Conventions used in this document		1.1. Conventions used in this document
	The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",		The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
	"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this		"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
	document are to be interpreted as described in [RFC2119].		document are to be interpreted as described in [RFC2119].
	1.2 Problem Statement		1.2. Problem Statement
	Addresses generated using Stateless address autoconfiguration		Addresses generated using Stateless address autoconfiguration
	[ADDRCONF]contain an embedded interface identifier, which remains		[ADDRCONF]contain an embedded interface identifier, which remains
	constant over time. Anytime a fixed identifier is used in multiple		constant over time. Anytime a fixed identifier is used in multiple
	contexts, it becomes possible to correlate seemingly unrelated		contexts, it becomes possible to correlate seemingly unrelated
	activity using this identifier.		activity using this identifier.
	The correlation can be performed by		The correlation can be performed by
	o An attacker who is in the path between the node in question and		o An attacker who is in the path between the node in question and
	skipping to change at page 5, line 11 ¶		skipping to change at page 5, line 11 ¶
	Use of temporary addresses will not prevent such payload based		Use of temporary addresses will not prevent such payload based
	correlation.		correlation.
	2. Background		2. Background
	This section discusses the problem in more detail, provides context		This section discusses the problem in more detail, provides context
	for evaluating the significance of the concerns in specific		for evaluating the significance of the concerns in specific
	environments and makes comparisons with existing practices.		environments and makes comparisons with existing practices.
	2.1 Extended Use of the Same Identifier		2.1. Extended Use of the Same Identifier
	The use of a non-changing interface identifier to form addresses is a		The use of a non-changing interface identifier to form addresses is a
	specific instance of the more general case where a constant		specific instance of the more general case where a constant
	identifier is reused over an extended period of time and in multiple		identifier is reused over an extended period of time and in multiple
	independent activities. Anytime the same identifier is used in		independent activities. Anytime the same identifier is used in
	multiple contexts, it becomes possible for that identifier to be used		multiple contexts, it becomes possible for that identifier to be used
	to correlate seemingly unrelated activity. For example, a network		to correlate seemingly unrelated activity. For example, a network
	sniffer placed strategically on a link across which all traffic to/		sniffer placed strategically on a link across which all traffic to/
	from a particular host crosses could keep track of which destinations		from a particular host crosses could keep track of which destinations
	a node communicated with and at what times. Such information can in		a node communicated with and at what times. Such information can in
	skipping to change at page 6, line 18 ¶		skipping to change at page 6, line 18 ¶
	The use of a constant identifier within an address is of special		The use of a constant identifier within an address is of special
	concern because addresses are a fundamental requirement of		concern because addresses are a fundamental requirement of
	communication and cannot easily be hidden from eavesdroppers and		communication and cannot easily be hidden from eavesdroppers and
	other parties. Even when higher layers encrypt their payloads,		other parties. Even when higher layers encrypt their payloads,
	addresses in packet headers appear in the clear. Consequently, if a		addresses in packet headers appear in the clear. Consequently, if a
	mobile host (e.g., laptop) accessed the network from several		mobile host (e.g., laptop) accessed the network from several
	different locations, an eavesdropper might be able to track the		different locations, an eavesdropper might be able to track the
	movement of that mobile host from place to place, even if the upper		movement of that mobile host from place to place, even if the upper
	layer payloads were encrypted.		layer payloads were encrypted.
	2.2 Address Usage in IPv4 Today		2.2. Address Usage in IPv4 Today
	Addresses used in today's Internet are often non-changing in practice		Addresses used in today's Internet are often non-changing in practice
	for extended periods of time. In an increasing number of sites,		for extended periods of time. In an increasing number of sites,
	addresses are assigned statically and typically change infrequently.		addresses are assigned statically and typically change infrequently.
	Over the last few years, sites have begun moving away from static		Over the last few years, sites have begun moving away from static
	allocation to dynamic allocation via DHCP [DHCP]. In theory, the		allocation to dynamic allocation via DHCP [DHCP]. In theory, the
	address a client gets via DHCP can change over time, but in practice		address a client gets via DHCP can change over time, but in practice
	servers often return the same address to the same client (unless		servers often return the same address to the same client (unless
	addresses are in such short supply that they are reused immediately		addresses are in such short supply that they are reused immediately
	by a different node when they become free). Thus, even within sites		by a different node when they become free). Thus, even within sites
	skipping to change at page 7, line 12 ¶		skipping to change at page 7, line 12 ¶
	used to update the DNS dynamically, it may not always be available		used to update the DNS dynamically, it may not always be available
	depending on the administrative policy. In addition, changing an		depending on the administrative policy. In addition, changing an
	address but keeping the same DNS name does not really address the		address but keeping the same DNS name does not really address the
	underlying concern, since the DNS name becomes a non-changing		underlying concern, since the DNS name becomes a non-changing
	identifier. Servers generally require a DNS name (so clients can		identifier. Servers generally require a DNS name (so clients can
	connect to them), and clients often do as well (e.g., some servers		connect to them), and clients often do as well (e.g., some servers
	refuse to speak to a client whose address cannot be mapped into a DNS		refuse to speak to a client whose address cannot be mapped into a DNS
	name that also maps back into the same address). Section 4 describes		name that also maps back into the same address). Section 4 describes
	one approach to this issue.		one approach to this issue.
	2.3 The Concern With IPv6 Addresses		2.3. The Concern With IPv6 Addresses
	The division of IPv6 addresses into distinct topology and interface		The division of IPv6 addresses into distinct topology and interface
	identifier portions raises an issue new to IPv6 in that a fixed		identifier portions raises an issue new to IPv6 in that a fixed
	portion of an IPv6 address (i.e., the interface identifier) can		portion of an IPv6 address (i.e., the interface identifier) can
	contain an identifier that remains constant even when the topology		contain an identifier that remains constant even when the topology
	portion of an address changes (e.g., as the result of connecting to a		portion of an address changes (e.g., as the result of connecting to a
	different part of the Internet). In IPv4, when an address changes,		different part of the Internet). In IPv4, when an address changes,
	the entire address (including the local part of the address) usually		the entire address (including the local part of the address) usually
	changes. It is this new issue that this document addresses.		changes. It is this new issue that this document addresses.
	skipping to change at page 8, line 12 ¶		skipping to change at page 8, line 12 ¶
	an address could be used to track activities of an individual, even		an address could be used to track activities of an individual, even
	as they move topologically within the internet.		as they move topologically within the internet.
	In summary, IPv6 addresses on a given interface generated via		In summary, IPv6 addresses on a given interface generated via
	Stateless Autoconfiguration contain the same interface identifier,		Stateless Autoconfiguration contain the same interface identifier,
	regardless of where within the Internet the device connects. This		regardless of where within the Internet the device connects. This
	facilitates the tracking of individual devices (and thus potentially		facilitates the tracking of individual devices (and thus potentially
	users). The purpose of this document is to define mechanisms that		users). The purpose of this document is to define mechanisms that
	eliminate this issue, in those situations where it is a concern.		eliminate this issue, in those situations where it is a concern.
	2.4 Possible Approaches		2.4. Possible Approaches
	One way to avoid having a static non-changing address is to use		One way to avoid having a static non-changing address is to use
	DHCPv6 [DHCPV6] for obtaining addresses. The DHCPv6 server could be		DHCPv6[DHCPV6] for obtaining addresses. Section 12 of [DHCPV6]
	configured to hand out addresses that change over time. But DHCPv6		discusses the use of DHCPv6 for the assignment and management of
	will solve the privacy issue only if it frequently handed out		"temporary addresses", which are never renewed and provide the same
	constantly changing addresses to the nodes or if the DHCPv6 client		property of temporary addresses described in this document with
	moves from links to links frequently, being allocated independent		regards to the privacy concern.
	addresses from different DHCPv6 servers. However, the former does
	not happen automatically, and is difficult to configure manually; the
	latter cannot be assumed for static (not frequently moving) hosts.
	Thus, DHCPv6 is not a self contained alternative for solving the
	privacy issues addressed by this document. However, in the absence
	of stateless address autoconfiguration, DHCPv6 can be used for
	distributing temporary addresses to clients.
	Another approach, compatible with the stateless address		Another approach, compatible with the stateless address
	autoconfiguration architecture, would be to change the interface		autoconfiguration architecture, would be to change the interface
	identifier portion of an address over time and generate new addresses		identifier portion of an address over time and generate new addresses
	from the interface identifier for some address scopes. Changing the		from the interface identifier for some address scopes. Changing the
	interface identifier can make it more difficult to look at the IP		interface identifier can make it more difficult to look at the IP
	addresses in independent transactions and identify which ones		addresses in independent transactions and identify which ones
	actually correspond to the same node, both in the case where the		actually correspond to the same node, both in the case where the
	routing prefix portion of an address changes and when it does not.		routing prefix portion of an address changes and when it does not.
	skipping to change at page 10, line 49 ¶		skipping to change at page 10, line 49 ¶
	multicast groups may be required to put its interface into		multicast groups may be required to put its interface into
	promiscuous mode, resulting in possible reduced performance.		promiscuous mode, resulting in possible reduced performance.
	A node highly concerned about privacy MAY use different interface		A node highly concerned about privacy MAY use different interface
	identifiers on different prefixes, resulting in a set of global		identifiers on different prefixes, resulting in a set of global
	addresses that cannot be easily tied to each other. For example		addresses that cannot be easily tied to each other. For example
	a node MAY create different interface identifiers I1,I2, and I3		a node MAY create different interface identifiers I1,I2, and I3
	for use with different prefixes P1,P2, and P3 on the same		for use with different prefixes P1,P2, and P3 on the same
	interface.		interface.
	3.1 Assumptions		3.1. Assumptions
	The following algorithm assumes that each interface maintains an		The following algorithm assumes that each interface maintains an
	associated randomized interface identifier. When temporary addresses		associated randomized interface identifier. When temporary addresses
	are generated, the current value of the associated randomized		are generated, the current value of the associated randomized
	interface identifier is used. While the same identifier can be used		interface identifier is used. While the same identifier can be used
	to create more than one temporary address, the value SHOULD change		to create more than one temporary address, the value SHOULD change
	over time as described in Section 3.5.		over time as described in Section 3.5.
	The algorithm also assumes that for a given temporary address, an		The algorithm also assumes that for a given temporary address, an
	implementation can determine the prefix from which it was generated.		implementation can determine the prefix from which it was generated.
	skipping to change at page 12, line 5 ¶		skipping to change at page 12, line 5 ¶
	[ADDR_SELECT] mandates implementations to provide a mechanism, which		[ADDR_SELECT] mandates implementations to provide a mechanism, which
	allows an application to configure its preference for temporary		allows an application to configure its preference for temporary
	addresses over public addresses. It also allows for an		addresses over public addresses. It also allows for an
	implementation to prefer temporary addresses by default, so that the		implementation to prefer temporary addresses by default, so that the
	connections initiated by the node can use temporary addresses without		connections initiated by the node can use temporary addresses without
	requiring application-specific enablement. This document also		requiring application-specific enablement. This document also
	assumes that an API will exist that allows individual applications to		assumes that an API will exist that allows individual applications to
	indicate whether they prefer to use temporary or public addresses and		indicate whether they prefer to use temporary or public addresses and
	override the system defaults.		override the system defaults.
	3.2 Generation Of Randomized Interface Identifiers		3.2. Generation Of Randomized Interface Identifiers
	We describe two approaches for the generation and maintenance of the		We describe two approaches for the generation and maintenance of the
	randomized interface identifier. The first assumes the presence of		randomized interface identifier. The first assumes the presence of
	stable storage that can be used to record state history for use as		stable storage that can be used to record state history for use as
	input into the next iteration of the algorithm across system		input into the next iteration of the algorithm across system
	restarts. A second approach addresses the case where stable storage		restarts. A second approach addresses the case where stable storage
	is unavailable and there is a need to generate randomized interface		is unavailable and there is a need to generate randomized interface
	identifiers without previous state.		identifiers without previous state.
	The random interface identifier generation algorithm, as described in		The random interface identifier generation algorithm, as described in
	this document, uses MD5 as the hash algorithm. The node MAY use		this document, uses MD5 as the hash algorithm. The node MAY use
	another algorithm instead of MD5 to produce the random interface		another algorithm instead of MD5 to produce the random interface
	identifier.		identifier.
	3.2.1 When Stable Storage Is Present		3.2.1. When Stable Storage Is Present
	The following algorithm assumes the presence of a 64-bit "history		The following algorithm assumes the presence of a 64-bit "history
	value" that is used as input in generating a randomized interface		value" that is used as input in generating a randomized interface
	identifier. The very first time the system boots (i.e., out-of-the-		identifier. The very first time the system boots (i.e., out-of-the-
	box), a random value SHOULD be generated using techniques that help		box), a random value SHOULD be generated using techniques that help
	ensure the initial value is hard to guess [RANDOM]. Whenever a new		ensure the initial value is hard to guess [RANDOM]. Whenever a new
	interface identifier is generated, a value generated by the		interface identifier is generated, a value generated by the
	computation is saved in the history value for the next iteration of		computation is saved in the history value for the next iteration of
	the algorithm.		the algorithm.
	skipping to change at page 13, line 13 ¶		skipping to change at page 13, line 13 ¶
	obtained in step 2 in place of the history value in step 1.		obtained in step 2 in place of the history value in step 1.
	5. Save the generated identifier as the associated randomized		5. Save the generated identifier as the associated randomized
	interface identifier.		interface identifier.
	6. Take the rightmost 64-bits of the MD5 digest computed in step 2)		6. Take the rightmost 64-bits of the MD5 digest computed in step 2)
	and save them in stable storage as the history value to be used		and save them in stable storage as the history value to be used
	in the next iteration of the algorithm.		in the next iteration of the algorithm.
	MD5 was chosen for convenience, and because its particular properties		MD5 was chosen for convenience, and because its particular properties
	were adequate to produce the desired level of randomization. IPv6		were adequate to produce the desired level of randomization.The node
	nodes are already required to implement MD5 as part of IPsec [IPSEC],		MAY use another algorithm instead of MD5 to produce the random
	thus the code will already be present on IPv6 machines.		interface identifier
	In theory, generating successive randomized interface identifiers		In theory, generating successive randomized interface identifiers
	using a history scheme as above has no advantages over generating		using a history scheme as above has no advantages over generating
	them at random. In practice, however, generating truly random		them at random. In practice, however, generating truly random
	numbers can be tricky. Use of a history value is intended to avoid		numbers can be tricky. Use of a history value is intended to avoid
	the particular scenario where two nodes generate the same randomized		the particular scenario where two nodes generate the same randomized
	interface identifier, both detect the situation via DAD, but then		interface identifier, both detect the situation via DAD, but then
	proceed to generate identical randomized interface identifiers via		proceed to generate identical randomized interface identifiers via
	the same (flawed) random number generation algorithm. The above		the same (flawed) random number generation algorithm. The above
	algorithm avoids this problem by having the interface identifier		algorithm avoids this problem by having the interface identifier
	(which will often be globally unique) used in the calculation that		(which will often be globally unique) used in the calculation that
	generates subsequent randomized interface identifiers. Thus, if two		generates subsequent randomized interface identifiers. Thus, if two
	nodes happen to generate the same randomized interface identifier,		nodes happen to generate the same randomized interface identifier,
	they should generate different ones on the followup attempt.		they should generate different ones on the followup attempt.
	3.2.2 In The Absence of Stable Storage		3.2.2. In The Absence of Stable Storage
	In the absence of stable storage, no history value will be available		In the absence of stable storage, no history value will be available
	across system restarts to generate a pseudo-random sequence of		across system restarts to generate a pseudo-random sequence of
	interface identifiers. Consequently, the initial history value used		interface identifiers. Consequently, the initial history value used
	above SHOULD be generated at random. A number of techniques might be		above SHOULD be generated at random. A number of techniques might be
	appropriate. Consult [RANDOM] for suggestions on good sources for		appropriate. Consult [RANDOM] for suggestions on good sources for
	obtaining random numbers. Note that even though machines may not		obtaining random numbers. Note that even though machines may not
	have stable storage for storing a history value, they will in many		have stable storage for storing a history value, they will in many
	cases have configuration information that differs from one machine to		cases have configuration information that differs from one machine to
	another (e.g., user identity, security keys, serial numbers, etc.).		another (e.g., user identity, security keys, serial numbers, etc.).
	One approach to generating a random initial history value in such		One approach to generating a random initial history value in such
	cases is to use the configuration information to generate some data		cases is to use the configuration information to generate some data
	bits (which may remain constant for the life of the machine, but will		bits (which may remain constant for the life of the machine, but will
	vary from one machine to another), append some random data and		vary from one machine to another), append some random data and
	compute the MD5 digest as before.		compute the MD5 digest as before.
	3.2.3 Alternate approaches		3.2.3. Alternate approaches
	Note that there are other approaches to generate random interface		Note that there are other approaches to generate random interface
	identifiers, albeit with different goals and applicability. One such		identifiers, albeit with different goals and applicability. One such
	approach is CGA [CGA], which generates a random interface identifier		approach is CGA [CGA], which generates a random interface identifier
	based on the public key of the node. The goal of CGAs is to prove		based on the public key of the node. The goal of CGAs is to prove
	ownership of an address and to prevent spoofing and stealing of		ownership of an address and to prevent spoofing and stealing of
	existing IPv6 addresses. They are used for securing neighbor		existing IPv6 addresses. They are used for securing neighbor
	discovery using [SEND]. The CGA random interface identifier		discovery using [SEND]. The CGA random interface identifier
	generation algorithm may not be suitable for privacy addresses		generation algorithm may not be suitable for privacy addresses
	because of the following properties		because of the following properties
	o It requires the node to have a public key. This means that the		o It requires the node to have a public key. This means that the
	node can still be identified by its public key		node can still be identified by its public key
	o The random interface identifier process is computationally		o The random interface identifier process is computationally
	intensive and hence discourages frequent regeneration		intensive and hence discourages frequent regeneration
	3.3 Generating Temporary Addresses		3.3. Generating Temporary Addresses
	[ADDRCONF] describes the steps for generating a link-local address		[ADDRCONF] describes the steps for generating a link-local address
	when an interface becomes enabled as well as the steps for generating		when an interface becomes enabled as well as the steps for generating
	addresses for other scopes. This document extends [ADDRCONF] as		addresses for other scopes. This document extends [ADDRCONF] as
	follows. When processing a Router Advertisement with a Prefix		follows. When processing a Router Advertisement with a Prefix
	Information option carrying a global scope prefix for the purposes of		Information option carrying a global scope prefix for the purposes of
	address autoconfiguration (i.e., the A bit is set), the node MUST		address autoconfiguration (i.e., the A bit is set), the node MUST
	perform the following steps:		perform the following steps:
	1. Process the Prefix Information Option as defined in [ADDRCONF],		1. Process the Prefix Information Option as defined in [ADDRCONF],
	skipping to change at page 15, line 16 ¶		skipping to change at page 15, line 15 ¶
	3. When a new public address is created as described in [ADDRCONF],		3. When a new public address is created as described in [ADDRCONF],
	the node SHOULD also create a new temporary address.		the node SHOULD also create a new temporary address.
	4. When creating a temporary address, the lifetime values MUST be		4. When creating a temporary address, the lifetime values MUST be
	derived from the corresponding prefix as follows:		derived from the corresponding prefix as follows:
	* Its Valid Lifetime is the lower of the Valid Lifetime of the		* Its Valid Lifetime is the lower of the Valid Lifetime of the
	public address or TEMP_VALID_LIFETIME		public address or TEMP_VALID_LIFETIME
	* Its Preferred Lifetime is the lower of the Preferred Lifetime		* Its Preferred Lifetime is the lower of the Preferred Lifetime
	of the prefix or TEMP_PREFERRED_LIFETIME - DESYNC_FACTOR.		of the public address or TEMP_PREFERRED_LIFETIME -
			DESYNC_FACTOR.
	5. A temporary address is created only if this calculated Preferred		5. A temporary address is created only if this calculated Preferred
	Lifetime is greater than REGEN_ADVANCE time units. In		Lifetime is greater than REGEN_ADVANCE time units. In
	particular, an implementation MUST NOT create a temporary address		particular, an implementation MUST NOT create a temporary address
	with a zero Preferred Lifetime.		with a zero Preferred Lifetime.
	6. New temporary addresses MUST be created by appending the		6. New temporary addresses MUST be created by appending the
	interface's current randomized interface identifier to the prefix		interface's current randomized interface identifier to the prefix
	that was received.		that was received.
	skipping to change at page 15, line 38 ¶		skipping to change at page 15, line 38 ¶
	generated temporary address. If DAD indicates the address is		generated temporary address. If DAD indicates the address is
	already in use, the node MUST generate a new randomized interface		already in use, the node MUST generate a new randomized interface
	identifier as described in Section 3.2 above, and repeat the		identifier as described in Section 3.2 above, and repeat the
	previous steps as appropriate up to TEMP_IDGEN_RETRIES times. If		previous steps as appropriate up to TEMP_IDGEN_RETRIES times. If
	after TEMP_IDGEN_RETRIES consecutive attempts no non-unique		after TEMP_IDGEN_RETRIES consecutive attempts no non-unique
	address was generated, the node MUST log a system error and MUST		address was generated, the node MUST log a system error and MUST
	NOT attempt to generate temporary addresses for that interface.		NOT attempt to generate temporary addresses for that interface.
	Note that DAD MUST be performed on every unicast address		Note that DAD MUST be performed on every unicast address
	generated from this randomized interface identifier.		generated from this randomized interface identifier.
	3.4 Expiration of Temporary Addresses		3.4. Expiration of Temporary Addresses
	When a temporary address becomes deprecated, a new one MUST be		When a temporary address becomes deprecated, a new one MUST be
	generated. This is done by repeating the actions described in		generated. This is done by repeating the actions described in
	Section 3.3, starting at step 3). Note that, except for the		Section 3.3, starting at step 3). Note that, except for the
	transient period when a temporary address is being regenerated, in		transient period when a temporary address is being regenerated, in
	normal operation at most one temporary address per prefix should be		normal operation at most one temporary address per prefix should be
	in a non-deprecated state at any given time on a given interface.		in a non-deprecated state at any given time on a given interface.
	Note that if a temporary address becomes deprecated as result of		Note that if a temporary address becomes deprecated as result of
	processing a Prefix Information Option with a zero Preferred		processing a Prefix Information Option with a zero Preferred
	Lifetime, then a new temporary address MUST NOT be generated. To		Lifetime, then a new temporary address MUST NOT be generated. To
	skipping to change at page 16, line 15 ¶		skipping to change at page 16, line 13 ¶
	race conditions in the case where generating a new temporary address		race conditions in the case where generating a new temporary address
	is not instantaneous, such as when duplicate address detection must		is not instantaneous, such as when duplicate address detection must
	be run. The node SHOULD start the address regeneration process		be run. The node SHOULD start the address regeneration process
	REGEN_ADVANCE time units before a temporary address would actually be		REGEN_ADVANCE time units before a temporary address would actually be
	deprecated.		deprecated.
	As an optional optimization, an implementation MAY remove a		As an optional optimization, an implementation MAY remove a
	deprecated temporary address that is not in use by applications or		deprecated temporary address that is not in use by applications or
	upper-layers as detailed in Section 6.		upper-layers as detailed in Section 6.
	3.5 Regeneration of Randomized Interface Identifiers		3.5. Regeneration of Randomized Interface Identifiers
	The frequency at which temporary addresses changes depends on how a		The frequency at which temporary addresses changes depends on how a
	device is being used (e.g., how frequently it initiates new		device is being used (e.g., how frequently it initiates new
	communication) and the concerns of the end user. The most egregious		communication) and the concerns of the end user. The most egregious
	privacy concerns appear to involve addresses used for long periods of		privacy concerns appear to involve addresses used for long periods of
	time (weeks to months to years). The more frequently an address		time (weeks to months to years). The more frequently an address
	changes, the less feasible collecting or coordinating information		changes, the less feasible collecting or coordinating information
	keyed on interface identifiers becomes. Moreover, the cost of		keyed on interface identifiers becomes. Moreover, the cost of
	collecting information and attempting to correlate it based on		collecting information and attempting to correlate it based on
	interface identifiers will only be justified if enough addresses		interface identifiers will only be justified if enough addresses
	skipping to change at page 17, line 25 ¶		skipping to change at page 17, line 23 ¶
	new set of temporary addresses. If a device moves from one ethernet		new set of temporary addresses. If a device moves from one ethernet
	to another, generating a new set of temporary addresses from a		to another, generating a new set of temporary addresses from a
	different randomized interface identifier ensures that the device		different randomized interface identifier ensures that the device
	uses different randomized interface identifiers for the temporary		uses different randomized interface identifiers for the temporary
	addresses associated with the two links, making it more difficult to		addresses associated with the two links, making it more difficult to
	correlate addresses from the two different links as being from the		correlate addresses from the two different links as being from the
	same node. The node MAY follow any process available to it, to		same node. The node MAY follow any process available to it, to
	determine that the link change has occurred. One such process is		determine that the link change has occurred. One such process is
	described by Detecting Network Attachment [DNA].		described by Detecting Network Attachment [DNA].
	3.6 Deployment Considerations		3.6. Deployment Considerations
	Devices implementing this specification MUST provide a way for the		Devices implementing this specification MUST provide a way for the
	end user to explicitly enable or disable the use of temporary		end user to explicitly enable or disable the use of temporary
	addresses. In addition, a site might wish to disable the use of		addresses. In addition, a site might wish to disable the use of
	temporary addresses in order to simplify network debugging and		temporary addresses in order to simplify network debugging and
	operations. Consequently, implementations SHOULD provide a way for		operations. Consequently, implementations SHOULD provide a way for
	trusted system administrators to enable or disable the use of		trusted system administrators to enable or disable the use of
	temporary addresses.		temporary addresses.
	Additionally, sites might wish to selectively enable or disable the		Additionally, sites might wish to selectively enable or disable the
	skipping to change at page 21, line 38 ¶		skipping to change at page 22, line 5 ¶
	problem described in Section 4 when reverse DNS lookups fail may be		problem described in Section 4 when reverse DNS lookups fail may be
	needed. [DNSOP] contains a more detailed discussion of the DNS		needed. [DNSOP] contains a more detailed discussion of the DNS
	related issues.		related issues.
	While this document discusses ways of obscuring a user's permanent IP		While this document discusses ways of obscuring a user's permanent IP
	address, the method described is believed to be ineffective against		address, the method described is believed to be ineffective against
	sophisticated forms of traffic analysis. To increase effectiveness,		sophisticated forms of traffic analysis. To increase effectiveness,
	one may need to consider use of more advanced techniques, such as		one may need to consider use of more advanced techniques, such as
	Onion Routing [ONION].		Onion Routing [ONION].
	Open Issues		7. Security Considerations
	1) Implementations should allow system administrators to configure		Ingress filtering has been and is being deployed as a means of
	the use of temporary addresses. We've considered the possibility of		preventing the use of spoofed source addresses in Distributed Denial
	using Router Advertisements to configure a host's use of temporary		of Service(DDoS) attacks. In a network with a large number of nodes,
	addresses, but that has a major drawback: in some situations (for		new temporary addresses are created at a fairly high rate. This
	example a home user receiving RAs from an ISP's router), the		might make it difficult for ingress filtering mechanisms to
	administrator of the host and the administrator of the router may		distinguish between legitimately changing temporary addresses and
	have different opinions about the use of temporary addresses. Any		spoofed source addresses, which are "in-prefix"(They use a
	configuration mechanism that disables the use of temporary addresses		topologically correct prefix and non-existent interface ID). This
	without input from the user MUST ensure that the host's administrator		can be addressed by using access control mechanisms on a per address
	has authorized the disabling.		basis on the network egress point.
	7. Significant Changes from RFC 3041		8. Significant Changes from RFC 3041
	This section summarizes the changes in this document relative to RFC		This section summarizes the changes in this document relative to RFC
	3041 that an implementer of RFC 3041 should be aware of.		3041 that an implementer of RFC 3041 should be aware of.
	1. Added wording to exclude certain interface identifiers from the		1. Excluded certain interface identifiers from the range of
	range of acceptable interface identifiers. Interface IDs such		acceptable interface identifiers. Interface IDs such as those
	as 0, those for reserved anycast addresses [RFC2526], etc.		for reserved anycast addresses [RFC], etc.
	2. Added a configuration knob that provides the end user with a way
	to enable or disable the use of temporary addresses.
	3. Under RFC 3041, RAs with short lifetimes (e.g., 1 hour) that
	always send the same lifetime for long periods of time (e.g.,
	days to weeks) resulted in temporary addresses being created
	with lifetimes of only 1 hour. Additional rules were added to
	increase the Lifetime of temporary addresses when the advertised
	lifetimes were short.
	4. DAD is now run on all temporary addresses, not just the first
	one generated from an interface identifier.
	5. Changed the default setting for usage of temporary addresses to
	be disabled.
	6. Added a security considerations section to highlight the ingress
	filtering issues which can be caused by the use of temporary
	addresses as described in this document
	7. Removed references to site-local addresses
	8. Added a check for denial of service attacks using low valid
	lifetimes in router advertisements
	9. Changed the document to use RFC2119 language
	10. The node is now allowed to generate different interface
	identifiers for different prefixes, if it so desires.
	8. Changes from version 00
	This section summarizes the changes from version 00 of this draft
	1. The algorithm used for generating random interface identifiers
	is no longer restricted to just MD5
	2. Added a problem statement
	3. Classified the references into normative and informative
	4. Reduced default number of retries to 3 from 5 and added a
	configuration variable
	5. Removed text about RA processing which is duplicated from
	[ADDRCONF]
	6. Added text about the privacy implications of a non-changing
	prefix
	7. Added a per-prefix enable/disable setting
	8. Added text about the means of correlation
	9. Clarified text about DHCPv6
	10. Added reference to dnsop issues draft
	9. Changes from version 01
	This section summarizes the changes from version 01 of this draft
	1. Clarifiying the length of interface identifier
	2. Added a per-prefix enable/disable knob as a SHOULD to retain
	backward compatibility
	3. Removed normative reference to ISATAP to avoid downref problem
	4. Added text for per-prefix knobs to be applied at any granularity
	5. Moved RFC2526 to informative reference
	10. Changes from version 02
	This section summarizes the changes from version 02 of this draft
	1. Explained briefly the concern that is being addressed in the
	introduction
	2. Removed reference to 64 bit identifiers in the ADDRCONF context
	3. Added clarifying text for the usage of DHCPv6 as an alternate
	approach
	4. Moved RFC3484 to informative reference
	5. Updated references for SEND, and CGA as they became RFCs
	6. Updated draft versions for ULA, DNSOP issues, 2461bis, 2462bis		2. Added a configuration knob that provides the end user with a way
	and DNA goals		to enable or disable the use of temporary addresses on a per-
			prefix basis.
	11. Changes from version 03		3. Added a check for denial of service attacks using low valid
			lifetimes in router advertisements
	This section summarizes the changes from version 03 of this draft		4. DAD is now run on all temporary addresses, not just the first one
			generated from an interface identifier.
	1. Added additional clarifying text regarding regeneration of		5. Changed the default setting for usage of temporary addresses to
	identifiers as proposed in the AD(Margaret Wasserman) review		be disabled.
	comments.
	2. Clarified confusing text which seemed to imply that the randomnly		6. The node is now allowed to generate different interface
	generated identigiers could only be used with global scope		identifiers for different prefixes, if it so desires.
	addresses.
	3. Switched to the new IPR boilerplate		7. The algorithm used for generating random interface identifiers is
			no longer restricted to just MD5
	12. Security Considerations		8. Reduced default number of retries to from and added a
			configuration variable
	Ingress filtering has been and is being deployed as a means of		9. RA processing algorithm is no longer included in the document,
	preventing the use of spoofed source addresses in Distributed Denial		and is replaced by a reference to [ADDRCONF].
	of Service(DDoS) attacks. In a network with a large number of nodes,
	new temporary addresses are created at a fairly high rate. This
	might make it difficult for ingress filtering mechanisms to
	distinguish between legitimately changing temporary addresses and
	spoofed source addresses, which are "in-prefix"(They use a
	topologically correct prefix and non-existent interface ID). This
	can be addressed by using access control mechanisms on a per address
	basis on the network egress point.
	13. Acknowledgements		9. Acknowledgements
	The authors would like to acknowledge the contributions of the ipv6		The authors would like to acknowledge the contributions of the ipv6
	working group and, in particular, Ran Atkinson, Matt Crawford, Steve		working group and, in particular, Ran Atkinson, Matt Crawford, Steve
	Deering, Allison Mankin, Peter Bieringer, Jari Arkko, Pekka Nikander,		Deering, Allison Mankin, Peter Bieringer, Jari Arkko, Pekka Nikander,
	Pekka Savola, Francis Dupont, Brian Haberman, Tatuya Jinmei and		Pekka Savola, Francis Dupont, Brian Haberman, Tatuya Jinmei and
	Margaret Wasserman for their detailed comments.		Margaret Wasserman for their detailed comments.
	14. References		10. References
	14.1 Normative References		10.1. Normative References
	[ADDRARCH]		[ADDRARCH]
	Hinden, R. and S. Deering, "Internet Protocol Version 6		Hinden, R. and S. Deering, "Internet Protocol Version 6
	(IPv6) Addressing Architecture", RFC 3513, April 2003.		(IPv6) Addressing Architecture", RFC 3513, April 2003.
	[ADDRCONF]		[ADDRCONF]
	Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless		Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
	Address Autoconfiguration", draft-ietf-ipv6-rfc2462bis-07		Address Autoconfiguration", draft-ietf-ipv6-rfc2462bis-07
	(work in progress), December 2004.		(work in progress), December 2004.
	[DISCOVERY]		[DISCOVERY]
	Narten, T., Nordmark, E., Simpson, W., and H. Soliman,		Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
	"Neighbor Discovery for IP version 6 (IPv6)",		"Neighbor Discovery for IP version 6 (IPv6)",
	draft-ietf-ipv6-2461bis-02 (work in progress),		draft-ietf-ipv6-2461bis-02 (work in progress),
	February 2005.		February 2005.
	[IPSEC] Kent, S. and R. Atkinson, "Security Architecture for the
	Internet Protocol", RFC 2401, November 1998.
	[MD5] Rivest, R., "The MD5 Message-Digest Algorithm", RFC 1321,		[MD5] Rivest, R., "The MD5 Message-Digest Algorithm", RFC 1321,
	April 1992.		April 1992.
	[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate		[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
	Requirement Levels", RFC 2119, March 1997.		Requirement Levels", RFC 2119, March 1997.
	14.2 Informative References		10.2. Informative References
	[ADDR_SELECT]		[ADDR_SELECT]
	Draves, R., "Default Address Selection for Internet		Draves, R., "Default Address Selection for Internet
	Protocol version 6 (IPv6)", RFC 3484, February 2003.		Protocol version 6 (IPv6)", RFC 3484, February 2003.
	[CGA] Aura, T., "Cryptographically Generated Addresses (CGA)",		[CGA] Aura, T., "Cryptographically Generated Addresses (CGA)",
	RFC 3972, March 2005.		RFC 3972, March 2005.
	[COOKIES] Kristol, D. and L. Montulli, "HTTP State Management		[COOKIES] Kristol, D. and L. Montulli, "HTTP State Management
	Mechanism", RFC 2965, October 2000.		Mechanism", RFC 2965, October 2000.
	skipping to change at page 30, line 24 ¶		skipping to change at page 26, line 22 ¶
	October 2004.		October 2004.
	[ONION] Reed, MGR., Syverson, PFS., and DMG. Goldschlag, "Proxies		[ONION] Reed, MGR., Syverson, PFS., and DMG. Goldschlag, "Proxies
	for Anonymous Routing", Proceedings of the 12th Annual		for Anonymous Routing", Proceedings of the 12th Annual
	Computer Security Applications Conference, San Diego, CA,		Computer Security Applications Conference, San Diego, CA,
	December 1996.		December 1996.
	[RANDOM] Eastlake, D., Crocker, S., and J. Schiller, "Randomness		[RANDOM] Eastlake, D., Crocker, S., and J. Schiller, "Randomness
	Recommendations for Security", RFC 1750, December 1994.		Recommendations for Security", RFC 1750, December 1994.
	[RFC2526] Johnson, D. and S. Deering, "Reserved IPv6 Subnet Anycast
	Addresses", RFC 2526, March 1999.
	[SEND] Arkko, J., Kempf, J., Zill, B., and P. Nikander, "SEcure		[SEND] Arkko, J., Kempf, J., Zill, B., and P. Nikander, "SEcure
	Neighbor Discovery (SEND)", RFC 3971, March 2005.		Neighbor Discovery (SEND)", RFC 3971, March 2005.
	[ULA] Hinden, R. and B. Haberman, "Unique Local IPv6 Unicast		[ULA] Hinden, R. and B. Haberman, "Unique Local IPv6 Unicast
	Addresses", draft-ietf-ipv6-unique-local-addr-09 (work in		Addresses", draft-ietf-ipv6-unique-local-addr-09 (work in
	progress), January 2005.		progress), January 2005.
	Authors' Addresses		Authors' Addresses
	Thomas Narten		Thomas Narten
	skipping to change at page 32, line 41 ¶		skipping to change at page 28, line 41 ¶
	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 AND THE INTERNET
	ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,		ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
	INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE		INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
	INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED		INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
	WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.		WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
	Copyright Statement		Copyright Statement
	Copyright (C) The Internet Society (2005). This document is subject		Copyright (C) The Internet Society (2006). This document is subject
	to the rights, licenses and restrictions contained in BCP 78, and		to the rights, licenses and restrictions contained in BCP 78, and
	except as set forth therein, the authors retain all their rights.		except as set forth therein, the authors retain all their rights.
	Acknowledgment		Acknowledgment
	Funding for the RFC Editor function is currently provided by the		Funding for the RFC Editor function is currently provided by the
	Internet Society.		Internet Society.
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