draft-ietf-6man-ra-pref64-02.txt		draft-ietf-6man-ra-pref64-03.txt
	IPv6 Maintenance L. Colitti		IPv6 Maintenance L. Colitti
	Internet-Draft J. Linkova		Internet-Draft J. Linkova
	Intended status: Standards Track Google		Intended status: Standards Track Google
	Expires: January 23, 2020 July 22, 2019		Expires: January 25, 2020 July 24, 2019
	Discovering PREF64 in Router Advertisements		Discovering PREF64 in Router Advertisements
	draft-ietf-6man-ra-pref64-02		draft-ietf-6man-ra-pref64-03
	Abstract		Abstract
	This document specifies a Router Advertisement option to communicate		This document specifies a Router Advertisement option to communicate
	NAT64 prefixes to clients.		NAT64 prefixes to clients.
	Status of This Memo		Status of This Memo
	This Internet-Draft is submitted in full conformance with the		This Internet-Draft is submitted in full conformance with the
	provisions of BCP 78 and BCP 79.		provisions of BCP 78 and BCP 79.
	skipping to change at page 1, line 31 ¶		skipping to change at page 1, line 31 ¶
	Internet-Drafts are working documents of the Internet Engineering		Internet-Drafts are working documents of the Internet Engineering
	Task Force (IETF). Note that other groups may also distribute		Task Force (IETF). Note that other groups may also distribute
	working documents as Internet-Drafts. The list of current Internet-		working documents as Internet-Drafts. The list of current Internet-
	Drafts is at https://datatracker.ietf.org/drafts/current/.		Drafts is at https://datatracker.ietf.org/drafts/current/.
	Internet-Drafts are draft documents valid for a maximum of six months		Internet-Drafts are draft documents valid for a maximum of six months
	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."
	This Internet-Draft will expire on January 23, 2020.		This Internet-Draft will expire on January 25, 2020.
	Copyright Notice		Copyright Notice
	Copyright (c) 2019 IETF Trust and the persons identified as the		Copyright (c) 2019 IETF Trust and the persons identified as the
	document authors. All rights reserved.		document authors. All rights reserved.
	This document is subject to BCP 78 and the IETF Trust's Legal		This document is subject to BCP 78 and the IETF Trust's Legal
	Provisions Relating to IETF Documents		Provisions Relating to IETF Documents
	(https://trustee.ietf.org/license-info) in effect on the date of		(https://trustee.ietf.org/license-info) in effect on the date of
	publication of this document. Please review these documents		publication of this document. Please review these documents
	skipping to change at page 2, line 16 ¶		skipping to change at page 2, line 16 ¶
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
	1.1. Requirements Language . . . . . . . . . . . . . . . . . . 2		1.1. Requirements Language . . . . . . . . . . . . . . . . . . 2
	1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 2		1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 2
	2. Use cases for communicating the NAT64 prefix to hosts . . . . 3		2. Use cases for communicating the NAT64 prefix to hosts . . . . 3
	3. Why include the NAT64 prefix in Router Advertisements . . . . 3		3. Why include the NAT64 prefix in Router Advertisements . . . . 3
	4. Semantics . . . . . . . . . . . . . . . . . . . . . . . . . . 4		4. Semantics . . . . . . . . . . . . . . . . . . . . . . . . . . 4
	5. Option format . . . . . . . . . . . . . . . . . . . . . . . . 4		5. Option format . . . . . . . . . . . . . . . . . . . . . . . . 4
	6. Handling Multiple NAT64 Prefixes . . . . . . . . . . . . . . 6		6. Handling Multiple NAT64 Prefixes . . . . . . . . . . . . . . 6
	7. Multihoming . . . . . . . . . . . . . . . . . . . . . . . . . 7		7. Multihoming . . . . . . . . . . . . . . . . . . . . . . . . . 7
	8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8		8. Pref64 Consistency . . . . . . . . . . . . . . . . . . . . . 8
	9. Security Considerations . . . . . . . . . . . . . . . . . . . 8		9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
	10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8		10. Security Considerations . . . . . . . . . . . . . . . . . . . 8
	11. References . . . . . . . . . . . . . . . . . . . . . . . . . 8		11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 9
	11.1. Normative References . . . . . . . . . . . . . . . . . . 8		12. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
	11.2. Informative References . . . . . . . . . . . . . . . . . 9		12.1. Normative References . . . . . . . . . . . . . . . . . . 9
	11.3. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 10		12.2. Informative References . . . . . . . . . . . . . . . . . 9
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10		12.3. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 11
			Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11
	1. Introduction		1. Introduction
	NAT64 [RFC6146] with DNS64 [RFC6147] is a widely-deployed mechanism		NAT64 [RFC6146] with DNS64 [RFC6147] is a widely-deployed mechanism
	to provide IPv4 access on IPv6-only networks. In various scenarios,		to provide IPv4 access on IPv6-only networks. In various scenarios,
	the host must be aware of the NAT64 prefix in use by the network.		the host must be aware of the NAT64 prefix in use by the network.
	This document specifies a Router Advertisement [RFC4861] option to		This document specifies a Router Advertisement [RFC4861] option to
	communicate the NAT64 prefix to hosts.		communicate the NAT64 prefix to hosts.
	1.1. Requirements Language		1.1. Requirements Language
	skipping to change at page 5, line 15 ¶		skipping to change at page 5, line 15 ¶
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Type | Length | Lifetime |		| Type | Length | Lifetime |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| |		| |
	+ +		+ +
	| Highest 96 bits of the Prefix |		| Highest 96 bits of the Prefix |
	+ +		+ +
	| |		| |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Prefix Length | Reserved |		| Lowest bits (96-127) of the prefix (optional, if Length > 2) |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Reserved |		| Prefix Length | Reserved |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	Figure 1: NAT64 Prefix Option Format		Figure 1: NAT64 Prefix Option Format
	Fields:		Fields:
	Type 8-bit identifier of the Pref64 option type as assigned by		Type 8-bit identifier of the Pref64 option type as assigned by
	IANA: TBD		IANA: TBD
	Length 8-bit unsigned integer. The length of the option (including		Length 8-bit unsigned integer. The length of the option (including
	the Type and Length fields) is in units of 8 octets. If the		the Type and Length fields) is in units of 8 octets. If the
	skipping to change at page 6, line 30 ¶		skipping to change at page 6, line 30 ¶
	which this NAT64 prefix MAY be used. The value of Lifetime		which this NAT64 prefix MAY be used. The value of Lifetime
	SHOULD by default be set to lesser of 3 x MaxRtrAdvInterval		SHOULD by default be set to lesser of 3 x MaxRtrAdvInterval
	or 65535 seconds. A value of zero means that the prefix		or 65535 seconds. A value of zero means that the prefix
	MUST no longer be used.		MUST no longer be used.
	Highest 96-bit unsigned integer. Contains bits 0 - 95 of the NAT64		Highest 96-bit unsigned integer. Contains bits 0 - 95 of the NAT64
	96 bits prefix.		96 bits prefix.
	of the		of the
	prefix		prefix
			Lowest 32-bit unsigned integer. Contains bits 96 - 127 of the NAT64
			bits of prefix. This field is optional and presents only if the
			the prefix length is not 96 bits.
			prefix
	Prefix 8-bit unsigned integer. Optional field which present only if		Prefix 8-bit unsigned integer. Optional field which present only if
	Length the prefix length is not 96 bits. The sender MUST set it		Length the prefix length is not 96 bits. The sender MUST set it
	only to one of the following values: 32, 40, 48, 56, 64		only to one of the following values: 32, 40, 48, 56, 64
	([RFC6052]. The receiver MUST ignore the Pref64 option if		([RFC6052]. The receiver MUST ignore the Pref64 option if
	the prefix length value is not set to one of those numbers.		the prefix length value is not set to one of those numbers.
	Reserved A 7-byte unused field. It MUST be initialized to zero by		Reserved A 3-byte unused field. If present it MUST be initialized to
	the sender and MUST be ignored by the receiver. This field		zero by the sender and MUST be ignored by the receiver. This
	is optional and presents only if the prefix length is not 96		field is optional and presents only if the prefix length is
	bits.		not 96 bits.
	6. Handling Multiple NAT64 Prefixes		6. Handling Multiple NAT64 Prefixes
	In some cases a host may receive multiple NAT64 prefixes from		In some cases a host may receive multiple NAT64 prefixes from
	different sources. Possible scenarios include (but are not limited		different sources. Possible scenarios include (but are not limited
	to):		to):
	o the host is using multiple mechanisms to discover Pref64 prefixes		o the host is using multiple mechanisms to discover Pref64 prefixes
	(e.g. by using PCP ([RFC7225]) and/or by resolving IPv4-only fully		(e.g. by using PCP ([RFC7225]) and/or by resolving IPv4-only fully
	qualified domain name ([RFC7050]) in addition to receiving the		qualified domain name ([RFC7050]) in addition to receiving the
	skipping to change at page 8, line 5 ¶		skipping to change at page 8, line 11 ¶
	requires the host to support the concept of multiple Provisioning		requires the host to support the concept of multiple Provisioning
	Domains (PvD, a set of configuration information associated with a		Domains (PvD, a set of configuration information associated with a
	network, [RFC7556]) and to be able to use these PvDs.		network, [RFC7556]) and to be able to use these PvDs.
	This issue is not specific to the Pref64 RA option and, for example,		This issue is not specific to the Pref64 RA option and, for example,
	is quite typical for DNS resolving on multihomed hosts (e.g. a host		is quite typical for DNS resolving on multihomed hosts (e.g. a host
	might resolve a destination name by using the corporate DNS server		might resolve a destination name by using the corporate DNS server
	via the VPN tunnel but then send the traffic via its Internet-facing		via the VPN tunnel but then send the traffic via its Internet-facing
	interface).		interface).
	8. IANA Considerations		8. Pref64 Consistency
			Section 6.2.7 of [RFC4861] recommends that routers inspects RAs sent
			by other routers to ensure that all routers onlink advertise the
			consistent information. Routers SHOULD inspect valid Pref64 options
			received on a given link and verify the consistency. Detected
			inconsistencies indicate that one or more routers might be
			misconfigured. Routers SHOULD log such cases to system or network
			management. Routers SHOULD check and compare the following
			information:
			o set of Pref64 with non-zero lifetime;
			o set of Pref64 with zero lifetime.
			PvD-aware routers MUST only compare information scoped to the same
			implicit or explicit PvD.
			9. IANA Considerations
	The IANA is requested to assign a new IPv6 Neighbor Discovery Option		The IANA is requested to assign a new IPv6 Neighbor Discovery Option
	type for the PREF64 option defined in this document.		type for the PREF64 option defined in this document.
	+---------------+-------+		+---------------+-------+
	| Option Name | Type |		| Option Name | Type |
	+---------------+-------+		+---------------+-------+
	| PREF64 option | (TBD) |		| PREF64 option | (TBD) |
	+---------------+-------+		+---------------+-------+
	Table 1		Table 1
	The IANA registry for these options is:		The IANA registry for these options is:
	https://www.iana.org/assignments/icmpv6-parameters [1]		https://www.iana.org/assignments/icmpv6-parameters [1]
	9. Security Considerations		10. Security Considerations
	Because Router Advertisements are required in all IPv6 configuration		Because Router Advertisements are required in all IPv6 configuration
	scenarios, on IPv6-only networks, Router Advertisements must already		scenarios, on IPv6-only networks, Router Advertisements must already
	be secured, e.g., by deploying RA guard [RFC6105]. Providing all		be secured, e.g., by deploying RA guard [RFC6105]. Providing all
	configuration in Router Advertisements increases security by ensuring		configuration in Router Advertisements increases security by ensuring
	that no other protocols can be abused by malicious attackers to		that no other protocols can be abused by malicious attackers to
	provide hosts with invalid configuration.		provide hosts with invalid configuration.
	The security measures that must already be in place to ensure that		The security measures that must already be in place to ensure that
	Router Advertisements are only received from legitimate sources		Router Advertisements are only received from legitimate sources
	eliminate the problem of NAT64 prefix validation described in section		eliminate the problem of NAT64 prefix validation described in section
	3.1 of [RFC7050].		3.1 of [RFC7050].
	10. Acknowledgements		11. Acknowledgements
	Thanks to the following people (in alphabetical order) for their		Thanks to the following people (in alphabetical order) for their
	review and feedback: Mikael Abrahamsson, Mark Andrews, Brian E		review and feedback: Mikael Abrahamsson, Mark Andrews, Brian E
	Carpenter, Nick Heatley, Martin Hunek, Tatuya Jinmei, Erik Kline,		Carpenter, Nick Heatley, Martin Hunek, Tatuya Jinmei, Erik Kline,
	Michael Richardson, David Schinazi.		Michael Richardson, David Schinazi.
	11. References		12. References
	11.1. Normative References		12.1. Normative References
	[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate		[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
	Requirement Levels", BCP 14, RFC 2119,		Requirement Levels", BCP 14, RFC 2119,
	DOI 10.17487/RFC2119, March 1997,		DOI 10.17487/RFC2119, March 1997,
	<https://www.rfc-editor.org/info/rfc2119>.		<https://www.rfc-editor.org/info/rfc2119>.
	[RFC6052] Bao, C., Huitema, C., Bagnulo, M., Boucadair, M., and X.		[RFC6052] Bao, C., Huitema, C., Bagnulo, M., Boucadair, M., and X.
	Li, "IPv6 Addressing of IPv4/IPv6 Translators", RFC 6052,		Li, "IPv6 Addressing of IPv4/IPv6 Translators", RFC 6052,
	DOI 10.17487/RFC6052, October 2010,		DOI 10.17487/RFC6052, October 2010,
	<https://www.rfc-editor.org/info/rfc6052>.		<https://www.rfc-editor.org/info/rfc6052>.
	11.2. Informative References		12.2. Informative References
	[I-D.ietf-intarea-provisioning-domains]		[I-D.ietf-intarea-provisioning-domains]
	Pfister, P., Vyncke, E., Pauly, T., Schinazi, D., and W.		Pfister, P., Vyncke, E., Pauly, T., Schinazi, D., and W.
	Shao, "Discovering Provisioning Domain Names and Data",		Shao, "Discovering Provisioning Domain Names and Data",
	draft-ietf-intarea-provisioning-domains-05 (work in		draft-ietf-intarea-provisioning-domains-05 (work in
	progress), June 2019.		progress), June 2019.
	[RFC4033] Arends, R., Austein, R., Larson, M., Massey, D., and S.		[RFC4033] Arends, R., Austein, R., Larson, M., Massey, D., and S.
	Rose, "DNS Security Introduction and Requirements",		Rose, "DNS Security Introduction and Requirements",
	RFC 4033, DOI 10.17487/RFC4033, March 2005,		RFC 4033, DOI 10.17487/RFC4033, March 2005,
	skipping to change at page 10, line 24 ¶		skipping to change at page 11, line 5 ¶
	[RFC7858] Hu, Z., Zhu, L., Heidemann, J., Mankin, A., Wessels, D.,		[RFC7858] Hu, Z., Zhu, L., Heidemann, J., Mankin, A., Wessels, D.,
	and P. Hoffman, "Specification for DNS over Transport		and P. Hoffman, "Specification for DNS over Transport
	Layer Security (TLS)", RFC 7858, DOI 10.17487/RFC7858, May		Layer Security (TLS)", RFC 7858, DOI 10.17487/RFC7858, May
	2016, <https://www.rfc-editor.org/info/rfc7858>.		2016, <https://www.rfc-editor.org/info/rfc7858>.
	[RFC8305] Schinazi, D. and T. Pauly, "Happy Eyeballs Version 2:		[RFC8305] Schinazi, D. and T. Pauly, "Happy Eyeballs Version 2:
	Better Connectivity Using Concurrency", RFC 8305,		Better Connectivity Using Concurrency", RFC 8305,
	DOI 10.17487/RFC8305, December 2017,		DOI 10.17487/RFC8305, December 2017,
	<https://www.rfc-editor.org/info/rfc8305>.		<https://www.rfc-editor.org/info/rfc8305>.
	11.3. URIs		12.3. URIs
	[1] https://www.iana.org/assignments/icmpv6-parameters		[1] https://www.iana.org/assignments/icmpv6-parameters
	Authors' Addresses		Authors' Addresses
	Lorenzo Colitti		Lorenzo Colitti
	Google		Google
	Roppongi 6-10-1		Roppongi 6-10-1
	Minato, Tokyo 106-6126		Minato, Tokyo 106-6126
	JP		JP
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