draft-ietf-hip-dns-02.txt		draft-ietf-hip-dns-03.txt
	Network Working Group P. Nikander		Network Working Group P. Nikander
	Internet-Draft Ericsson Research Nomadic Lab		Internet-Draft Ericsson Research Nomadic Lab
	Expires: January 14, 2006 J. Laganier		Expires: April 13, 2006 J. Laganier
	DoCoMo Euro-Labs		DoCoMo Euro-Labs
	July 11, 2005		October 10, 2005
	Host Identity Protocol (HIP) Domain Name System (DNS) Extensions		Host Identity Protocol (HIP) Domain Name System (DNS) Extensions
	draft-ietf-hip-dns-02		draft-ietf-hip-dns-03
	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
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	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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	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 January 14, 2006.		This Internet-Draft will expire on April 13, 2006.
	Copyright Notice		Copyright Notice
	Copyright (C) The Internet Society (2005).		Copyright (C) The Internet Society (2005).
	Abstract		Abstract
	This document specifies two new resource records (RRs) for the Domain		This document specifies two new resource records (RRs) for the Domain
	Name System (DNS), and how to use them with the Host Identity		Name System (DNS), and how to use them with the Host Identity
	Protocol (HIP). These RRs allow a HIP node to store in the DNS its		Protocol (HIP). These RRs allow a HIP node to store in the DNS its
	Host Identity (HI, the public component of the node public-private		Host Identity (HI, the public component of the node public-private
	key pair), Host Identity Tag (HIT, a truncated hash of its public		key pair), Host Identity Tag (HIT, a truncated hash of its public
	key), and the Domain Name or IP addresses of its Rendezvous Servers		key), and the Domain Name or IP addresses of its rendezvous servers
	(RVS).		(RVS).
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
	2. Conventions used in this document . . . . . . . . . . . . . . 6		2. Conventions used in this document . . . . . . . . . . . . . . 6
	3. Usage Scenarios . . . . . . . . . . . . . . . . . . . . . . . 7		3. Usage Scenarios . . . . . . . . . . . . . . . . . . . . . . . 7
	3.1 Simple static singly homed end-host . . . . . . . . . . . 8		3.1. Simple static singly homed end-host . . . . . . . . . . . 8
	3.2 Mobile end-host . . . . . . . . . . . . . . . . . . . . . 9		3.2. Mobile end-host . . . . . . . . . . . . . . . . . . . . . 9
	3.3 Mixed Scenario . . . . . . . . . . . . . . . . . . . . . . 10		3.3. Mixed Scenario . . . . . . . . . . . . . . . . . . . . . . 10
	4. Overview of using the DNS with HIP . . . . . . . . . . . . . . 12		4. Overview of using the DNS with HIP . . . . . . . . . . . . . . 12
	4.1 Storing HI and HIT in DNS . . . . . . . . . . . . . . . . 12		4.1. Storing HI and HIT in DNS . . . . . . . . . . . . . . . . 12
	4.1.1 Different types of HITs . . . . . . . . . . . . . . . 12		4.1.1. HI and HIT Verification . . . . . . . . . . . . . . . 12
	4.2 Storing Rendezvous Servers in the DNS . . . . . . . . . . 13		4.2. Storing Rendezvous Servers in the DNS . . . . . . . . . . 12
	4.3 Initiating connections based on DNS names . . . . . . . . 13		4.3. Initiating connections based on DNS names . . . . . . . . 12
	5. Storage Format . . . . . . . . . . . . . . . . . . . . . . . . 14		5. Storage Format . . . . . . . . . . . . . . . . . . . . . . . . 13
	5.1 HIPHI RDATA format . . . . . . . . . . . . . . . . . . . . 14		5.1. HIPHI RDATA format . . . . . . . . . . . . . . . . . . . . 13
	5.1.1 HIT type format . . . . . . . . . . . . . . . . . . . 14		5.1.1. PK algorithm format . . . . . . . . . . . . . . . . . 13
	5.1.2 HIT algorithm format . . . . . . . . . . . . . . . . . 14		5.1.2. HIT length format . . . . . . . . . . . . . . . . . . 13
	5.1.3 PK algorithm format . . . . . . . . . . . . . . . . . 15		5.1.3. HIT format . . . . . . . . . . . . . . . . . . . . . . 13
	5.1.4 HIT format . . . . . . . . . . . . . . . . . . . . . . 15		5.1.4. Public key format . . . . . . . . . . . . . . . . . . 13
	5.1.5 Public key format . . . . . . . . . . . . . . . . . . 15		5.2. HIPRVS RDATA format . . . . . . . . . . . . . . . . . . . 14
	5.2 HIPRVS RDATA format . . . . . . . . . . . . . . . . . . . 16		5.2.1. Preference format . . . . . . . . . . . . . . . . . . 14
	5.2.1 Preference format . . . . . . . . . . . . . . . . . . 16		5.2.2. Rendezvous server type format . . . . . . . . . . . . 14
	5.2.2 Rendezvous server type format . . . . . . . . . . . . 16		5.2.3. Rendezvous server format . . . . . . . . . . . . . . . 15
	5.2.3 Rendezvous server format . . . . . . . . . . . . . . . 17		6. Presentation Format . . . . . . . . . . . . . . . . . . . . . 16
	6. Presentation Format . . . . . . . . . . . . . . . . . . . . . 18		6.1. HIPHI Representation . . . . . . . . . . . . . . . . . . . 16
	6.1 HIPHI Representation . . . . . . . . . . . . . . . . . . . 18		6.2. HIPRVS Representation . . . . . . . . . . . . . . . . . . 16
	6.2 HIPRVS Representation . . . . . . . . . . . . . . . . . . 18		6.3. Examples . . . . . . . . . . . . . . . . . . . . . . . . . 16
	6.3 Examples . . . . . . . . . . . . . . . . . . . . . . . . . 19		7. Retrieving Multiple HITs and IPs from the DNS . . . . . . . . 18
	7. Retrieving Multiple HITs and IPs from the DNS . . . . . . . . 20		8. Security Considerations . . . . . . . . . . . . . . . . . . . 19
	8. Security Considerations . . . . . . . . . . . . . . . . . . . 21		8.1. Attacker tampering with an insecure HIPHI RR . . . . . . . 19
	8.1 Attacker tampering with an unsecure HIPHI RR . . . . . . . 21		8.2. Attacker tampering with an insecure HIPRVS RR . . . . . . 19
	8.2 Attacker tampering with an unsecure HIPRVS RR . . . . . . 21		8.3. Opportunistic HIP . . . . . . . . . . . . . . . . . . . . 20
	8.3 Opportunistic HIP . . . . . . . . . . . . . . . . . . . . 22		8.4. Unpublished Initiator HI . . . . . . . . . . . . . . . . . 20
	8.4 Unpublished Initiator HI . . . . . . . . . . . . . . . . . 22		8.5. Hash and HITs Collisions . . . . . . . . . . . . . . . . . 20
	8.5 Hash and HITs Collisions . . . . . . . . . . . . . . . . . 22		8.6. DNSSEC . . . . . . . . . . . . . . . . . . . . . . . . . . 20
	8.6 DNSSEC . . . . . . . . . . . . . . . . . . . . . . . . . . 22		9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 21
	9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 23		10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 22
	10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . 25		11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 23
	11. References . . . . . . . . . . . . . . . . . . . . . . . . . 26		11.1. Normative references . . . . . . . . . . . . . . . . . . . 23
	11.1 Normative references . . . . . . . . . . . . . . . . . . . 26		11.2. Informative references . . . . . . . . . . . . . . . . . . 24
	11.2 Informative references . . . . . . . . . . . . . . . . . . 27		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 25
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 27		Intellectual Property and Copyright Statements . . . . . . . . . . 26
	Intellectual Property and Copyright Statements . . . . . . . . 28
	1. Introduction		1. Introduction
	This document specifies two new resource records (RRs) for the Domain		This document specifies two new resource records (RRs) for the Domain
	Name System (DNS) [1], and how to use them with the Host Identity		Name System (DNS) [RFC1034], and how to use them with the Host
	Protocol (HIP) [11]. These RRs allow a HIP node to store in the DNS		Identity Protocol (HIP) [I-D.ietf-hip-base]. These RRs allow a HIP
	its Host Identity (HI, the public component of the node public-		node to store in the DNS its Host Identity (HI, the public component
	private key pair), Host Identity Tag (HIT, a truncated hash of its		of the node public-private key pair), Host Identity Tag (HIT, a
	HI), and the Domain Name or IP addresses of its Rendezvous Servers		truncated hash of its HI), and the Domain Name or IP addresses of its
	(RVS) [14].		rendezvous servers (RVS) [I-D.ietf-hip-rvs].
	The current Internet architecture defines two global namespaces: IP		The current Internet architecture defines two global namespaces: IP
	addresses and domain names. The Domain Name System provides a two		addresses and domain names. The Domain Name System provides a two
	way lookup between these two namespaces. The HIP architecture [12]		way lookup between these two namespaces. The HIP architecture
	defines a new third namespace, called the Host Identity Namespace.		[I-D.ietf-hip-arch] defines a new third namespace, called the Host
	This namespace is composed of Host Identifiers (HI) of HIP nodes.		Identity Namespace. This namespace is composed of Host Identifiers
	The Host Identity Tag (HIT) is one representation of an HI. This		(HI) of HIP nodes. The Host Identity Tag (HIT) is one representation
	representation is obtained by taking the output of a secure hash		of an HI. This representation is obtained by taking the output of a
	function applied to the HI, truncated to the IPv6 address size. HITs		secure hash function applied to the HI, truncated to the IPv6 address
	are supposed to be used in the place of IP addresses within most ULPs		size. HITs are supposed to be used in the place of IP addresses
	and applications.		within most ULPs and applications.
	The Host Identity Protocol [11] allows two HIP nodes to establish		The Host Identity Protocol [I-D.ietf-hip-base] allows two HIP nodes
	together a HIP Association. A HIP association is bound to the nodes		to establish together a HIP Association. A HIP association is bound
	HIs rather than to their IP address(es).		to the nodes HIs rather than to their IP address(es).
	A HIP node establish a HIP association by initiating a 4 way		A HIP node establish a HIP association by initiating a 4 way
	handshake where two parties, the Initiatior and Responder, exchange		handshake where two parties, the initiator and responder, exchange
	the I1, I2, R1 and R2 HIP packets (see section 5.3 of [11])		the I1, I2, R1 and R2 HIP packets (see section 5.3 of [I-D.ietf-hip-
			base])
	+-----+ +-----+		+-----+ +-----+
	| |-------I1------>| |		| |-------I1------>| |
	| I |<------R1-------| R |		| I |<------R1-------| R |
	| |-------I2------>| |		| |-------I2------>| |
	| |<------R2-------| |		| |<------R2-------| |
	+-----+ +-----+		+-----+ +-----+
	Although a HIP node can initiate HIP communication		Although a HIP node can initiate HIP communication
	"opportunistically", i.e., without a priori knowledge of its peer's		"opportunistically", i.e., without prior knowledge of its peer's HI,
	HI, doing so exposes both endpoints to Man-in-the-Middle attacks on		doing so exposes both endpoints to Man-in-the-Middle attacks on the
	the HIP handshake and its cryptographic protocol. Hence, there is a		HIP handshake and its cryptographic protocol. Hence, there is a
	desire to gain knowledge of peers' HI before applications and ULPs		desire to gain knowledge of peers' HI before applications and ULPs
	initiate communication. Because many applications use the Domain		initiate communication. Because many applications use the Domain
	Name System [1] to name nodes, DNS is a straightforward way to		Name System [RFC1034] to name nodes, DNS is a straightforward way to
	provision nodes with the HIP informations (i.e. HI and possibly RVS)		provision nodes with the HIP information (i.e. HI, HIT and possibly
	of nodes named in the DNS tree, without introducing or relying on an		RVS) of nodes named in the DNS tree, without introducing or relying
	additional piece of infrastructure. Note that without DNSSEC [3] the		on an additional piece of infrastructure. Note that in the absence
	Man-in-the-Middle attack evocated before has moved from the		of DNSSEC [RFC2065], the DNS name resolution is vulnerable to Man-in-
	opportunistic HIP handshake to the DNS name resolution; See also		the-Middle attack (See Section 8), and hence the HIP handshake is
	Section 8.		also vulnerable to a Man-in-the-Middle attack.
	The proposed HIP multi-homing mechanisms [13] allow a node to		The proposed HIP multi-homing mechanisms [I-D.ietf-hip-mm] allow a
	dynamically change its set of underlying IP addresses while		node to dynamically change its set of underlying IP addresses while
	maintaining IPsec SA and transport layer session survivability. The		maintaining IPsec SA and transport layer session survivability. The
	HIP rendezvous extensions [14] proposal allows a HIP node to maintain		HIP rendezvous extensions [I-D.ietf-hip-rvs] proposal allows a HIP
	HIP reachability while it is changing its current location (the node		node to maintain HIP reachability while it is changing its current
	IP address(es)). This rendezvous service is provided by a third		location (the node IP address(es)). This rendezvous service is
	party, the node's Rendezvous Server (RVS).		provided by a third party, the node's rendezvous server (RVS).
	+-----+		+-----+
	+--I1--->| RVS |---I1--+		+--I1--->| RVS |---I1--+
	| +-----+ |		| +-----+ |
	| v		| v
	+-----+ +-----+		+-----+ +-----+
	| |<------R1-------| |		| |<------R1-------| |
	| I |-------I2------>| R |		| I |-------I2------>| R |
	| |<------R2-------| |		| |<------R2-------| |
	+-----+ +-----+		+-----+ +-----+
	An initiator (I) willing to establish a HIP association with a		An initiator (I) willing to establish a HIP association with a
	responder (R) would typically initiate a HIP exchange by sending an		responder (R) would typically initiate a HIP exchange by sending an
	I1 towards the RVS IP address rather than towards the responder IP		I1 towards the RVS IP address rather than towards the responder IP
	address. Then, the RVS, noticing that the receiver HIT is not its		address. Then, the RVS, noticing that the receiver HIT is not its
	own, but the HIT of a HIP node registered for the rendezvous Service,		own, but the HIT of a HIP node registered for the rendezvous service,
	would relay the I1 to the responder. Typically the responder would		would relay the I1 to the responder. Typically the responder would
	then complete the exchange without further assistance from the RVS by		then complete the exchange without further assistance from the RVS by
	sending an R1 directly to the initiator IP address.		sending an R1 directly to the initiator IP address.
	Currently, most of the Internet applications that need to communicate		Currently, most of the Internet applications that need to communicate
	with a remote host first translate a domain name (often obtained via		with a remote host first translate a domain name (often obtained via
	user input) into one or more IP address(es). This step occurs prior		user input) into one or more IP address(es). This step occurs prior
	to communication with the remote host, and relies on a DNS lookup.		to communication with the remote host, and relies on a DNS lookup.
	With HIP, IP addresses are expected to be used mostly for on-the-wire		With HIP, IP addresses are expected to be used mostly for on-the-wire
	communication between end hosts, while most ULPs and applications		communication between end hosts, while most ULPs and applications use
	uses HIs or HITs instead (ICMP might be an example of an ULP not		HIs or HITs instead (ICMP might be an example of an ULP not using
	using them). Consequently, we need a means to translate a domain		them). Consequently, we need a means to translate a domain name into
	name into an HI. Using the DNS for this translation is pretty		an HI. Using the DNS for this translation is pretty straightforward:
	straightforward: We define a new HIPHI (HIP HI) resource record.		We define a new HIPHI (HIP HI) resource record. Upon query by an
	Upon query by an application or ULP for a FQDN -> IP lookup, the		application or ULP for a FQDN -> IP lookup, the resolver would then
	resolver would then additionally perform an FQDN -> HI lookup, and		additionally perform an FQDN -> HI lookup, and use it to construct
	use it to construct the resulting HI -> IP mapping (which is internal		the resulting HI -> IP mapping (which is internal to the HIP layer).
	to the HIP layer). The HIP layer uses the HI -> IP mapping to		The HIP layer uses the HI -> IP mapping to translate HIs and their
	translate HIs and their local representations (HITs, IPv4 and IPv6-		local representations (HITs, IPv4 and IPv6-compatible LSIs) into IP
	compatible LSIs) into IP addresses and vice versa.		addresses and vice versa.
	This draft introduces the following new DNS Resource Records:		This draft introduces the following new DNS Resource Records:
	- HIPHI, for storing Host Identifiers and Host Identity Tags		- HIPHI, for storing Host Identifiers and Host Identity Tags
	- HIPRVS, for storing rendezvous server information		- HIPRVS, for storing rendezvous server information
	2. Conventions used in this document		2. 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 [4].		document are to be interpreted as described in RFC2119 [RFC2119].
	3. Usage Scenarios		3. Usage Scenarios
	In this section, we briefly introduce a number of usage scenarios		In this section, we briefly introduce a number of usage scenarios
	where the DNS is useful with the Host Identity Protocol.		where the DNS is useful with the Host Identity Protocol.
	With HIP, most application and ULPs are unaware of the IP addresses		With HIP, most application and ULPs are unaware of the IP addresses
	used to carry packets on the wire. Consequently, a HIP node could		used to carry packets on the wire. Consequently, a HIP node could
	take advantage of having multiple IP addresses for fail-over,		take advantage of having multiple IP addresses for fail-over,
	redundancy, mobility, or renumbering, in a manner which is		redundancy, mobility, or renumbering, in a manner which is
	transparent to most ULPs and applications (because they are bound to		transparent to most ULPs and applications (because they are bound to
	HIs, hence they are agnostic to these IP address changes).		HIs, hence they are agnostic to these IP address changes).
	In these situations, a node wishing to be reachable by reference to		In these situations, a node wishing to be reachable by reference to
	its FQDN should store the following informations in the DNS:		its FQDN should store the following information in the DNS:
	o A set of IP address(es) through A and AAAA RRs.		o A set of IP address(es) through A and AAAA RRs.
	o A Host Identity (HI) and/or Host Identity Tag (HIT) through HIPHI		o A Host Identity (HI) and/or Host Identity Tag (HIT) through HIPHI
	RRs.		RRs.
	o An IP address or DNS name of its Rendezvous Server(s) (RVS)		o An IP address or DNS name of its rendezvous server(s) (RVS)
	through HIPRVS RRs.		through HIPRVS RRs.
	When a HIP node wants to initiate a communication with another HIP		When a HIP node wants to initiate a communication with another HIP
	node, it first needs to perform a HIP base exchange to set-up a HIP		node, it first needs to perform a HIP base exchange to set-up a HIP
	association towards its peer. Although such an exchange can be		association towards its peer. Although such an exchange can be
	initiated opportunistically, i.e., without a priori knowledge of the		initiated opportunistically, i.e., without prior knowledge of the
	responder's HI, by doing so both nodes knowingly risk man-in-the-		responder's HI, by doing so both nodes knowingly risk man-in-the-
	middle attacks on the HIP exchange. To prevent these attacks, it is		middle attacks on the HIP exchange. To prevent these attacks, it is
	recommended that the initiator first obtain the HI of the responder,		recommended that the initiator first obtain the HI of the responder,
	and then initiate the exchange. This can be done, for example,		and then initiate the exchange. This can be done, for example,
	through manual configuration or DNS lookups. Hence, a new HIPHI RR		through manual configuration or DNS lookups. Hence, a new HIPHI RR
	is introduced.		is introduced.
	When a HIP node is frequently changing its IP address(es), the		When a HIP node is frequently changing its IP address(es), the
	dynamic DNS update latency may prevent it from publishing its new IP		dynamic DNS update latency may prevent it from publishing its new IP
	address(es) in the DNS. For solving this problem, the HIP		address(es) in the DNS. For solving this problem, the HIP
	architecture introduces Rendezvous Servers (RVS). A HIP host uses a		architecture introduces rendezvous servers (RVS). A HIP host uses a
	Rendezvous Server as a Rendezvous point, to maintain reachability		rendezvous server as a rendezvous point, to maintain reachability
	with possible HIP initiators. Such a HIP node would publish in the		with possible HIP initiators. Such a HIP node would publish in the
	DNS its RVS IP address or DNS name in a HIPRVS RR, while keeping its		DNS its RVS IP address or DNS name in a HIPRVS RR, while keeping its
	RVS up-to-date with its current set of IP addresses.		RVS up-to-date with its current set of IP addresses.
	When a HIP node wants to initiate a HIP exchange with a responder it		When a HIP node wants to initiate a HIP exchange with a responder it
	will perform a number of DNS lookups. First the initiator will need		will perform a number of DNS lookups. Depending on the type of the
	to query for an A or AAAA record at the responders FQDN.		implementation, the order in which those lookups will be issued may
			vary. For instance, implementations using IP address in APIs may
			typically first query for A and/or AAAA records at the responder
			FQDN, while those using HIT in APIS may typically first query for
			HIPHI records.
			In the following we assume that the initiator first queries for A
			and/or AAAA records at the responder FQDN.
	If the query for the A and/or AAAA was responded to with a DNS answer		If the query for the A and/or AAAA was responded to with a DNS answer
	with RCODE=3 (Name Error), then the responder's information is not		with RCODE=3 (Name Error), then the responder's information is not
	present in the DNS and further queries SHOULD NOT be made.		present in the DNS and further queries SHOULD NOT be made.
	In case the query for the address records returned a DNS answer with		In case the query for the address records returned a DNS answer with
	RCODE=0 (No Error), then the initiator sends out two queries: One for		RCODE=0 (No Error), then the initiator sends out two queries: One for
	the HIPHI type and one for the HIPRVS type at the responder's FQDN.		the HIPHI type and one for the HIPRVS type at the responder's FQDN.
	Depending on the combinations of answer the situations described in		Depending on the combinations of answer the situations described in
	Section 3.1, Section 3.2 and Section 3.3 can occur.		Section 3.1, Section 3.2 and Section 3.3 can occur.
	Note that storing HIP RR information in the DNS at a FQDN which is		Note that storing HIP RR information in the DNS at a FQDN which is
	assigned to a non-HIP node might have ill effects on its reachability		assigned to a non-HIP node might have ill effects on its reachability
	by HIP nodes.		by HIP nodes.
	3.1 Simple static singly homed end-host		3.1. Simple static singly homed end-host
	A HIP node (R) with a single static network attachment, wishing to be		A HIP node (R) with a single static network attachment, wishing to be
	reachable by reference to its FQDN (www.example.com), would store in		reachable by reference to its FQDN (www.example.com), would store in
	the DNS, in addition to its IP address(es) (IP-R), its Host Identity		the DNS, in addition to its IP address(es) (IP-R), its Host Identity
	(HI-R) in a HIPHI resource record.		(HI-R) in a HIPHI resource record.
	An initiator willing to associate with a node would typically issue		An initiator willing to associate with a node would typically issue
	the following queries:		the following queries:
	QNAME=www.example.com, QTYPE=A		QNAME=www.example.com, QTYPE=A
	(QCLASS=IN is assumed and ommitted from the examples)		(QCLASS=IN is assumed and omitted from the examples)
	Which returns a DNS packet with RCODE=0 and one or more A RRs A with		Which returns a DNS packet with RCODE=0 and one or more A RRs A with
	the address of the responder (e.g. IP-R) in the answer section.		the address of the responder (e.g. IP-R) in the answer section.
	QNAME=www.example.com, QTYPE=HIPHI		QNAME=www.example.com, QTYPE=HIPHI
	Which returns a DNS packet with RCODE=0 and one or more HIPHI RRs		Which returns a DNS packet with RCODE=0 and one or more HIPHI RRs
	with the HIT and HI (e.g. HIT-R and HI-R) of the responder in the		with the HIT and HI (e.g. HIT-R and HI-R) of the responder in the
	answer section.		answer section.
	skipping to change at page 9, line 28		skipping to change at page 9, line 28
	| | [A IP-R ]		| | [A IP-R ]
	| | [HIPHI 10 3 2 HIT-R HI-R]		| | [HIPHI 10 3 2 HIT-R HI-R]
	| v		| v
	+-----+ +-----+		+-----+ +-----+
	| |--------------I1------------->| |		| |--------------I1------------->| |
	| I |<-------------R1--------------| R |		| I |<-------------R1--------------| R |
	| |--------------I2------------->| |		| |--------------I2------------->| |
	| |<-------------R2--------------| |		| |<-------------R2--------------| |
	+-----+ +-----+		+-----+ +-----+
	3.2 Mobile end-host		3.2. Mobile end-host
	A mobile HIP node (R) wishing to be reachable by reference to its		A mobile HIP node (R) wishing to be reachable by reference to its
	FQDN (www.example.com) would store in the DNS, possibly in addition		FQDN (www.example.com) would store in the DNS, possibly in addition
	to its IP address(es) (IP-R), its HI (HI-R) in a HIPHI RR, and the IP		to its IP address(es) (IP-R), its HI (HI-R) in a HIPHI RR, and the IP
	address(es) of its Rendezvous Server(s) (IP-RVS) in HIPRVS resource		address(es) of its rendezvous server(s) (IP-RVS) in HIPRVS resource
	record(s). The mobile HIP node also need to notify its Rendezvous		record(s). The mobile HIP node also needs to notify its rendezvous
	Servers of any change in its set of IP address(es).		servers of any change in its set of IP address(es).
	An initiator willing to associate with such mobile node would		An initiator willing to associate with such mobile node would
	typically issue the following queries:		typically issue the following queries:
	QNAME=www.example.com, QTYPE=A		QNAME=www.example.com, QTYPE=A
	Which returns a DNS packet with RCODE=0 and an empty answer section.		Which returns a DNS packet with RCODE=0 and an empty answer section.
	QNAME=www.example.com, QTYPE=HIPHI		QNAME=www.example.com, QTYPE=HIPHI
	Which returns a DNS packet with RCODE=0 and one or more HIPHI RRs		Which returns a DNS packet with RCODE=0 and one or more HIPHI RRs
	with the HIT and HI (e.g HIT-R and HI-R) of the responder in the		with the HIT and HI (e.g. HIT-R and HI-R) of the responder in the
	answer section.		answer section.
	QNAME=www.example.com, QTYPE=HIPRVS		QNAME=www.example.com, QTYPE=HIPRVS
	Which returns a DNS packet with RCODE=0 and one or more HIPRVS RRs		Which returns a DNS packet with RCODE=0 and one or more HIPRVS RRs
	containing IP address(es) (e.g IP-RVS) or FQDN(s) of RVS(s).		containing IP address(es) (e.g. IP-RVS) or FQDN(s) of RVS(s).
	[A? HIPRVS? HIPHI?]		[A? HIPRVS? HIPHI?]
	[www.example.com ] +-----+		[www.example.com ] +-----+
	+--------------------------------->| |		+--------------------------------->| |
	| | DNS |		| | DNS |
	| +--------------------------------| |		| +--------------------------------| |
	| | [A? HIPRVS? HIPHI? ] +-----+		| | [A? HIPRVS? HIPHI? ] +-----+
	| | [www.example.com ]		| | [www.example.com ]
	| | [HIPRVS 1 2 IP-RVS ]		| | [HIPRVS 1 2 IP-RVS ]
	| | [HIPHI 10 3 2 HIT-R HI-R]		| | [HIPHI 10 3 2 HIT-R HI-R]
	skipping to change at page 10, line 36		skipping to change at page 10, line 33
	+-----+ +-----+		+-----+ +-----+
	| |<---------------R1------------| |		| |<---------------R1------------| |
	| I |----------------I2----------->| R |		| I |----------------I2----------->| R |
	| |<---------------R2------------| |		| |<---------------R2------------| |
	+-----+ +-----+		+-----+ +-----+
	The initiator would then send an I1 to one of its RVS. Following,		The initiator would then send an I1 to one of its RVS. Following,
	the RVS will relay the I1 up to the mobile node, which will complete		the RVS will relay the I1 up to the mobile node, which will complete
	the HIP exchange.		the HIP exchange.
	3.3 Mixed Scenario		3.3. Mixed Scenario
	A HIP node might be configured with more than one IP address (multi-		A HIP node might be configured with more than one IP address (multi-
	homed), or Rendezvous Server (multi-reachable). In these cases, it		homed), or rendezvous server (multi-reachable). In these cases, it
	is possible that the DNS returns multiple A or AAAA RRs, as well as		is possible that the DNS returns multiple A or AAAA RRs, as well as
	HIPRVS containing one or multiple Rendezvous Servers. In addition to		HIPRVS containing one or multiple rendezvous servers. In addition to
	its set of IP address(es) (IP-R1, IP-R2), a multi-homed end-host		its set of IP address(es) (IP-R1, IP-R2), a multi-homed end-host
	would store in the DNS its HI (HI-R) in a HIPHI RR, and possibly the		would store in the DNS its HI (HI-R) in a HIPHI RR, and possibly the
	IP address(es) of its RVS(s) (IP-RVS1, IP-RVS2) in HIPRVS RRs.		IP address(es) of its RVS(s) (IP-RVS1, IP-RVS2) in HIPRVS RRs.
	An initiator willing to associate with such a node would typically		An initiator willing to associate with such a node would typically
	issue the following queries:		issue the following queries:
	QNAME=www.example.com, QTYPE=A		QNAME=www.example.com, QTYPE=A
	Which returns a DNS packet with RCODE=0 and one or more A or AAAA RRs		Which returns a DNS packet with RCODE=0 and one or more A or AAAA RRs
	containing IP address(es) (e.g IP-R1 and IP-R2) in the answer		containing IP address(es) (e.g. IP-R1 and IP-R2) in the answer
	section.		section.
	QNAME=www.example.com, QTYPE=HIPHI		QNAME=www.example.com, QTYPE=HIPHI
	Which returns a DNS packet with RCODE=0 and one or more HIPHI RRs		Which returns a DNS packet with RCODE=0 and one or more HIPHI RRs
	with the HIT and HI (e.g HIT-R and HI-R) of the responder in the		with the HIT and HI (e.g. HIT-R and HI-R) of the responder in the
	answer section.		answer section.
	QNAME=www.example.com, QTYPE=HIPRVS		QNAME=www.example.com, QTYPE=HIPRVS
	Which returns a DNS packet with RCODE=0 and one or more HIPRVS RRs		Which returns a DNS packet with RCODE=0 and one or more HIPRVS RRs
	containing IP address(es) (e.g IP-RVS1, IP-RVS2) or FQDN(s) of		containing IP address(es) (e.g. IP-RVS1, IP-RVS2) or FQDN(s) of
	RVS(s).		RVS(s).
	[A? HIPRVS? HIPHI?]		[A? HIPRVS? HIPHI?]
	[www.example.com ] +-----+		[www.example.com ] +-----+
	+--------------------------------->| |		+--------------------------------->| |
	| | DNS |		| | DNS |
	| +--------------------------------| |		| +--------------------------------| |
	| | [A? HIPRVS? HIPHI? ] +-----+		| | [A? HIPRVS? HIPHI? ] +-----+
	| | [www.example.com ]		| | [www.example.com ]
	| | [A IP-R1 ]		| | [A IP-R1 ]
	skipping to change at page 12, line 7		skipping to change at page 12, line 7
	| |---------------I2------------->| |		| |---------------I2------------->| |
	| |<--------------R2--------------| |		| |<--------------R2--------------| |
	+-----+ +-----+		+-----+ +-----+
	| ^		| ^
	| +------+ |		| +------+ |
	+-----I1----->| RVS2 |------I1------+		+-----I1----->| RVS2 |------I1------+
	+------+		+------+
	4. Overview of using the DNS with HIP		4. Overview of using the DNS with HIP
	4.1 Storing HI and HIT in DNS		4.1. Storing HI and HIT in DNS
	Any conforming implementation may store Host Identifiers in a DNS
	HIPHI RDATA format. An implementation may also store a HIT along
	with its associated HI. If a particular form of an HI or HIT does
	not already have a specified RDATA format, a new RDATA-like format
	SHOULD be defined for the HI or HIT.
	4.1.1 Different types of HITs
	There are two types of HITs. HITs of the first type, called Type 1
	HIT, consist of an 8-bit prefix followed by 120 bits of the hash of
	the public key. HITs of the second type (Type 2 HIT) consist of a
	Host Assigning Authority Field (HAA), and only the last 64 bits come
	from a SHA-1 hash of the Host Identity. This latter format for HIT
	is recommended for 'well known' systems. It is possible to support a
	resolution mechanism for these names in hierarchical directories,
	like the DNS.
	This document fully specifies only Type 2 HITs. Type 1 HITs are
	specified in Section 3.1 of [11].
	Note that the format how HITs are stored in the HIPHI RRs may be
	different form the format actually used in protocols, the HIP base
	exchange [11] included. This is because the DNS RR explicitly
	contains the HIT type and algorithm, while some protocols may prefer
	to use a prefix to indicate the HIT type. The implementations are
	expected to use the actual HI when comparing Host Identities.
	4.1.1.1 Host Assigning Authority (HAA) field
	The 64 bits of HAA supports two levels of delegation. The first is a
	registered assigning authority (RAA). The second is a registered
	identity (RI, commonly a company). The RAA is 24 bits with values
	assign sequentially by ICANN. The RI is 40 bits, also assigned
	sequentially but by the RAA.
	4.1.1.2 Storing HAA in HIPHI Resource Records
	Any conforming implementation may store a domain name Host Assigning		Any conforming implementation may store a Host Identity (HI) and its
	Authority (HAA) in a DNS HIPHI RDATA format. A HAA MUST be stored		associated Host Identity Tag (HIT) in a DNS HIPHI RDATA format. If a
	like a Type 2 HIT, while the least significant bits of the HIT		particular form of an HI does not already have a specified RDATA
	extracted from the HI hash output are set to zero, the Host Identity		format, a new RDATA-like format SHOULD be defined for the HI. HI and
	Length is set zero, and the Host Identity field is omitted. If a		HIT are defined in Section 3 of [I-D.ietf-hip-base].
	particular form of a HAA does not already have an associated HIT
	specified RDATA format, a new RDATA-like format SHOULD be defined for
	the HIT/HAA.
	4.1.1.3 HI and HIT verification		4.1.1. HI and HIT Verification
	Upon return of a HIPHI RR, a host MUST always calculate the HI-		Upon return of a HIPHI RR, a host MUST always calculate the HI-
	derivative HIT to be used in the HIP exchange, as specified in the		derivative HIT to be used in the HIP exchange, as specified in
	HIP architecture [12], while the HIT possibly embedded along SHOULD		Section 3 of the HIP base specification [I-D.ietf-hip-base], while
	only be used as an optimization (e.g. table lookup).		the HIT possibly embedded along SHOULD only be used as an
			optimization (e.g. table lookup).
	4.2 Storing Rendezvous Servers in the DNS		4.2. Storing Rendezvous Servers in the DNS
	The HIP Rendezvous server (HIPRVS) resource record indicates an		The HIP rendezvous server (HIPRVS) resource record indicates an
	address or a domain name of a RendezVous Server, towards which a HIP		address or a domain name of a rendezvous Server, towards which a HIP
	I1 packet might be sent to trigger the establishment of an		I1 packet might be sent to trigger the establishment of an
	association with the entity named by this resource record [14].		association with the entity named by this resource record [I-D.ietf-
			hip-rvs].
	An RVS receiving such an I1 would then relay it to the appropriate		An RVS receiving such an I1 would then relay it to the appropriate
	responder (the owner of the I1 receiver HIT). The responder will		responder (the owner of the I1 receiver HIT). The responder will
	then complete the exchange with the initiator, typically without		then complete the exchange with the initiator, typically without
	ongoing help from the RVS.		ongoing help from the RVS.
	Any conforming implementation may store Rendezvous Server's IP		Any conforming implementation may store rendezvous server's IP
	address(es) or DNS name in a DNS HIPRVS RDATA format. If a		address(es) or DNS name in a DNS HIPRVS RDATA format. If a
	particular form of a RVS reference does not already have a specified		particular form of a RVS reference does not already have a specified
	RDATA format, a new RDATA-like format SHOULD be defined for the RVS.		RDATA format, a new RDATA-like format SHOULD be defined for the RVS.
	4.3 Initiating connections based on DNS names		4.3. Initiating connections based on DNS names
	On a HIP node, a Host Identity Protocol exchange SHOULD be initiated		On a HIP node, a Host Identity Protocol exchange SHOULD be initiated
	whenever an Upper Layer Protocol attempt to communicate with an		whenever an Upper Layer Protocol attempt to communicate with an
	entity and the DNS lookup returns HIPHI and/or HIPRVS resource		entity and the DNS lookup returns HIPHI and/or HIPRVS resource
	records. If a DNS lookup returns one or more HIPRVS RRs and no A nor		records. If a DNS lookup returns one or more HIPRVS RRs and no A nor
	AAAA RRs, the afore mentioned HIP exchange SHOULD be initiated		AAAA RRs, the afore mentioned HIP exchange SHOULD be initiated
	towards one of these RVS [11]. Since some hosts may choose not to		towards one of these RVS [I-D.ietf-hip-base]. Since some hosts may
	have HIPHI information in DNS, hosts MAY implement support for		choose not to have HIPHI information in DNS, hosts MAY implement
	opportunistic HIP.		support for opportunistic HIP.
	5. Storage Format		5. Storage Format
	5.1 HIPHI RDATA format		5.1. HIPHI RDATA format
	The RDATA for a HIPHI RR consists of a HIT type, an algorithm type, a		The RDATA for a HIPHI RR consists of a public key algorithm type, the
	HIT, and a public key.		HIT length, a HIT, and a public key.
	0 1 2 3		0 1 2 3
	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
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| HIT type | HIT algorithm | PK algorithm | |		| PK algorithm | HIT length | |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ HIT |		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ HIT |
	~ ~		~ ~
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| /		| /
	/ Public Key /		/ Public Key /
	/ /		/ /
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-|		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-|
	5.1.1 HIT type format		The PK algorithm, HIT length, HIT and Public Key field are REQUIRED.
	The HIT type field indicates the Host Identity Tag (HIT) type and the
	implied HIT format.
	The following values are defined:
	0 No HIT is present
	1 A Type 1 HIT is present
	2 A Type 2 HIT is present
	3-6 Unassigned
	7 A HAA is present
	5.1.2 HIT algorithm format
	The HIT algorithm indicates the hash algorithm used to generate the
	Host Identity Tag (HIT) from the HI.
	The following values are defined:
	0 Reserved
	1 SHA1
	2-255 Unassigned
	5.1.3 PK algorithm format		5.1.1. PK algorithm format
	The PK algorithm field indicates the public key cryptographic		The PK algorithm field indicates the public key cryptographic
	algorithm and the implied public key field format. This document		algorithm and the implied public key field format. This document
	reuse the values defined for the 'algorithm type' of the IPSECKEY RR		reuse the values defined for the 'algorithm type' of the IPSECKEY RR
	[10] 'gateway type' field.		[RFC4025] 'gateway type' field.
	The presently defined values are given only informally:		The presently defined values are given only informally:
	1 A DSA key is present, in the format defined in RFC2536 [5].		1 A DSA key is present, in the format defined in RFC2536
			[RFC2536].
	2 A RSA key is present, in the format defined in RFC3110 [6].
	5.1.4 HIT format		2 A RSA key is present, in the format defined in RFC3110
			[RFC3110].
	There's currently two types of HITs, and a single type of HAA. Both		5.1.2. HIT length format
	of them are stored in network byte order within a self-describing
	variable length wire-encoded <character-string> (as per Section 3.3
	of [2]):
	o A *Type 1* HIT: least significant bits of the hash (e.g. SHA1) of		The HIT length indicates the length in bytes of the HIT field.
	the public key (Host Identity), which is possibly following in the
	HIPHI RR.
	o A *Type 2* HIT: binary prefix (HAA) concatenated with a the least		5.1.3. HIT format
	significant bits of the hash (e.g. SHA1) of the public key (Host
	Identity), which is possibly following in the HIPHI RR.
	o A HAA: binary prefix (HAA) concatenated with 0, up to the		The HIT is stored, as a binary value, in network byte order.
	associated HIT length.
	5.1.5 Public key format		5.1.4. Public key format
	Both of the public key types defined in this document (RSA and DSA)		Both of the public key types defined in this document (RSA and DSA)
	reuse the public key formats defined for the IPSECKEY RR [10] (which		reuse the public key formats defined for the IPSECKEY RR [RFC4025]
	in turns contains the algorithm-specific portion of the KEY RR RDATA,		(which in turns contains the algorithm-specific portion of the KEY RR
	all of the KEY RR DATA after the first four octets, corresponding to		RDATA, all of the KEY RR DATA after the first four octets,
	the same portion of the KEY RR that must be specified by documents		corresponding to the same portion of the KEY RR that must be
	that define a DNSSEC algorithm).		specified by documents that define a DNSSEC algorithm).
	In the future, if a new algorithm is to be used both by IPSECKEY RR		In the future, if a new algorithm is to be used both by IPSECKEY RR
	and HIPHI RR, it would probably use the same public key encodings for		and HIPHI RR, it would probably use the same public key encoding for
	both RRs. Unless specified otherwise, the HIPHI public key field		both RRs. Unless specified otherwise, the HIPHI public key field
	would use the same public key format as the IPSECKEY RR RDATA for the		would use the same public key format as the IPSECKEY RR RDATA for the
	corresponding algorithm.		corresponding algorithm.
	The DSA key format is defined in RFC2536 [5].		The DSA key format is defined in RFC2536 [RFC2536].
	The RSA key format is defined in RFC3110 [6] and the RSA key size		The RSA key format is defined in RFC3110 [RFC3110] and the RSA key
	limit (4096 bits) is relaxed in the IPSECKEY RR [10] specification.		size limit (4096 bits) is relaxed in the IPSECKEY RR [RFC4025]
			specification.
	5.2 HIPRVS RDATA format		5.2. HIPRVS RDATA format
	The RDATA for a HIPRVS RR consists of a preference value, a		The RDATA for a HIPRVS RR consists of a preference value, a
	Rendezvous server type and either one or more Rendezvous server		rendezvous server type and either one or more rendezvous server
	address, or one Rendezvous server domain name.		address, or one rendezvous server domain name.
	0 1 2 3		0 1 2 3
	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
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| preference | type | |		| preference | type | |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Rendezvous server |		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ rendezvous server |
	~ ~		~ ~
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	5.2.1 Preference format		The Preference and RVS Type fields are REQUIRED. At least one RVS
			field MUST be present.
			5.2.1. Preference format
	This is an unsigned 8-bit value, used to specify the preference given		This is an unsigned 8-bit value, used to specify the preference given
	to the RVS in the HIPRVS RR amongst others at the same owner. RVSs		to the RVS in the HIPRVS RR amongst others at the same owner. RVSs
	with lower values are preferred. If there is a tie within some RR		with lower values are preferred. If there is a tie within some RR
	subset, the initiating HIP host should pick one of the RVS randomly		subset, the initiating HIP host should pick one of the RVS randomly
	from the set of RRs, such that the requester load is fairly balanced		from the set of RRs, such that the requester load is fairly balanced
	amongst all RVSs of the set.		amongst all RVSs of the set.
	5.2.2 Rendezvous server type format		5.2.2. Rendezvous server type format
	The Rendezvous server type indicates the format of the information		The rendezvous server type indicates the format of the information
	stored in the Rendezvous server field.		stored in the rendezvous server field.
	This document reuses the type values for the 'gateway type' field of		This document reuses the type values for the 'gateway type' field of
	the IPSECKEY RR [10]. The presently defined values are given only		the IPSECKEY RR [RFC4025]. The presently defined values are given
	informally:		only informally:
	1. One or more 4-byte IPv4 address(es) in network byte order are		1. One or more 4-byte IPv4 address(es) in network byte order are
	present.		present.
	2. One or more 16-byte IPv6 address(es) in network byte order are		2. One or more 16-byte IPv6 address(es) in network byte order are
	present.		present.
	3. One or more variable length wire-encoded domain names as		3. One or more variable length wire-encoded domain names as
	described in section 3.3 of RFC1035 [2]. The wire-encoded format		described in section 3.3 of RFC1035 [RFC1035]. The wire-encoded
	is self-describing, so the length is implicit. The domain names		format is self-describing, so the length is implicit. The domain
	MUST NOT be compressed.		names MUST NOT be compressed.
	5.2.3 Rendezvous server format		5.2.3. Rendezvous server format
	The Rendezvous server field indicates one or more Rendezvous		The rendezvous server field indicates one or more rendezvous
	Server(s) IP address(es), or domain name(s). A HIP I1 packet sent to		server(s) IP address(es), or domain name(s). A HIP I1 packet sent to
	any of these RVS would reach the entity named by this resource		any of these RVS would reach the entity named by this resource
	record.		record.
	This document reuses the format used for the 'gateway' field of the		This document reuses the format used for the 'gateway' field of the
	IPSECKEY RR [10], but allows to concatenate several IP (v4 or v6)		IPSECKEY RR [RFC4025], but allows to concatenate several IP (v4 or
	addresses. The presently defined formats for the data portion of the		v6) addresses. The presently defined formats for the data portion of
	Rendezvous server field are given only informally:		the rendezvous server field are given only informally:
	o One or more 32-bit IPv4 address(es) in network byte order.		o One or more 32-bit IPv4 address(es) in network byte order.
	o One or more 128-bit IPv6 address(es) in network byte order.		o One or more 128-bit IPv6 address(es) in network byte order.
	o One or more variable length wire-encoded domain names as described		o One or more variable length wire-encoded domain names as described
	in section 3.3 of RFC1035 [2]. The wire-encoded format is self-		in Section 3.3 of RFC1035 [RFC1035]. The wire-encoded format is
	describing, so the length is implicit. The domain names MUST NOT		self-describing, so the length is implicit. The domain names MUST
	be compressed.		NOT be compressed.
	6. Presentation Format		6. Presentation Format
	This section specifies the representation of the HIPHI and HIPRVS RR		This section specifies the representation of the HIPHI and HIPRVS RR
	in a zone data master file.		in a zone data master file.
	6.1 HIPHI Representation		6.1. HIPHI Representation
	The HIT Type, HIT algorithm, PK algorithm, HIT and Public Key are		The PK algorithm field is represented as unsigned integers.
	REQUIRED.
	The HIT Type, HIT algorithm, and PK algorithm are represented as		The HIT length field is not represented as it is implicitly known
	unsigned integers.		thanks to the HIT field representation.
	The HIT field is represented as the Base16 encoding [8] (a.k.a. hex		The HIT field is represented as the Base16 encoding [RFC3548] (a.k.a.
	or hexadecimal) of the public key hash. The encoding MUST NOT		hex or hexadecimal) of the HIT. The encoding MUST NOT contains
	contains whitespace. If no HIT is to be indicated, then the HIT		whitespace(s).
	algorithm MUST be zero and the HIT field must be "." (a single dot
	character).
	The Public Key field is represented as the Base64 encoding [8] of the		The Public Key field is represented as the Base64 encoding [RFC3548]
	public key. The encoding MAY contains whitespace(s), and such		of the public key. The encoding MAY contains whitespace(s), and such
	whitespaces MUST be ignored.		whitespace(s) MUST be ignored.
	The complete representation of the HPIHI record is:		The complete representation of the HPIHI record is:
	IN HIPHI ( hit-type hit-algorithm pk-algorithm		IN HIPHI ( pk-algorithm
	base16-encoded-hit		base16-encoded-hit
	base64-encoded-public-key )		base64-encoded-public-key )
	6.2 HIPRVS Representation		6.2. HIPRVS Representation
	The Preference and RVS Type fields are REQUIRED. At least one RVS
	field MUST be present.
	The HIT Type, HIT algorithm, and PK algorithm are represented as
	unsigned integers.
	The RVS field is represented by one or more:		The RVS field is represented by one or more:
	o IPv4 dotted decimal address(es)		o IPv4 dotted decimal address(es)
	o IPv6 colon hex address(es)		o IPv6 colon hex address(es)
	o uncompressed domain name(s)		o uncompressed domain name(s)
	The complete representation of the HPIRVS record is:		The complete representation of the HPIRVS record is:
	IN HIPRVS ( preference rendezvous-server-type		IN HIPRVS ( preference rendezvous-server-type
	rendezvous-server[1]		rendezvous-server[1]
	...		...
	rendezvous-server[n] )		rendezvous-server[n] )
	6.3 Examples		6.3. Examples
	Example of a node with a HI but no HIT:
	www.example.com IN HIPHI ( 0 1 2
	.
	AB3NzaC1kc3MAAACBAOBhKn
	TCPOuFBzZQX/N3O9dm9P9iv
	UIMoId== )
	Example of a node with a HI and a HIT:		Example of a node with a HI and a HIT:
	www.example.com IN HIPHI ( 1 1 2		www.example.com IN HIPHI ( 2 2A20E0FF0FE8A52422D059FFFEA938A1
	AB3NzaC1kc3MAAACBAOBhKn		AB3NzaC1kc3MAAACBAOBhKn
	TCPOuFBzZQX/N3O9dm9P9iv		TCPOuFBzZQX/N3O9dm9P9iv
	UIMoId== )		UIMoId== )
	Example of a node with an IPv6 RVS:		Example of a node with an IPv6 RVS:
	www.example.com IN HIPRVS (10 2 2001:db8:200:1:20c:f1ff:feb:a533 )		www.example.com IN HIPRVS (10 2 2001:db8:200:1:20c:f1ff:feb:a533 )
	Example of a node with three IPv4 RVS:		Example of a node with three IPv4 RVS:
	skipping to change at page 20, line 34		skipping to change at page 18, line 34
	It is RECOMMENDED that if a host receives multiple HITs, the host		It is RECOMMENDED that if a host receives multiple HITs, the host
	SHOULD first try to initiate the base exchange by using the		SHOULD first try to initiate the base exchange by using the
	opportunistic mode. If the returned HIT does not match with any of		opportunistic mode. If the returned HIT does not match with any of
	the expected HITs, the host SHOULD retry by sending further I1s, one		the expected HITs, the host SHOULD retry by sending further I1s, one
	at time, trying out all of the listed HITs. If the host receives an		at time, trying out all of the listed HITs. If the host receives an
	R1 for any of the I1s, the host SHOULD continue to use the successful		R1 for any of the I1s, the host SHOULD continue to use the successful
	IP address until an R1 with a listed HIT is received, or the host has		IP address until an R1 with a listed HIT is received, or the host has
	tried all HITs, and try the other IP addresses only after that. A		tried all HITs, and try the other IP addresses only after that. A
	host MAY also send multiple I1s in parallel, but sending such I1s		host MAY also send multiple I1s in parallel, but sending such I1s
	MUST be rate limited to avoid flooding (as per Section 8.4.1 of		MUST be rate limited to avoid flooding (as per Section 8.4.1 of
	[11]).		[I-D.ietf-hip-base]).
	8. Security Considerations		8. Security Considerations
	Though the security considerations of the HIP DNS extensions still		Though the security considerations of the HIP DNS extensions still
	need to be more investigated and documented, this section contains a		need to be more investigated and documented, this section contains a
	description of the known threats involved with the usage of the HIP		description of the known threats involved with the usage of the HIP
	DNS extensions.		DNS extensions.
	In a manner similar to the IPSECKEY RR [10], the HIP DNS Extensions		In a manner similar to the IPSECKEY RR [RFC4025], the HIP DNS
	allows to provision two HIP nodes with the public keying material		Extensions allows to provision two HIP nodes with the public keying
	(HI) of their peer. These HIs will be subsequently used in a key		material (HI) of their peer. These HIs will be subsequently used in
	exchange between the peers. Hence, the HIP DNS Extensions introduce		a key exchange between the peers. Hence, the HIP DNS Extensions
	the same kind of threats that IPSECKEY does, plus threats caused by		introduce the same kind of threats that IPSECKEY does, plus threats
	the possibility given to a HIP node to initiate or accept a HIP		caused by the possibility given to a HIP node to initiate or accept a
	exchange using "Opportunistic" or "Unpublished Initiator HI" modes.		HIP exchange using "opportunistic" or "unpublished initiator HI"
			modes.
	A HIP node SHOULD obtain both the HIPHI and HIPRVS RRs from a trusted		A HIP node SHOULD obtain both the HIPHI and HIPRVS RRs from a trusted
	party trough a secure channel insuring proper data integrity of the		party trough a secure channel insuring proper data integrity of the
	RRs. DNSSEC [3] provides such a secure channel.		RRs. DNSSEC [RFC2065] provides such a secure channel.
	In the absence of a proper secure channel, both parties are		In the absence of a proper secure channel, both parties are
	vulnerable to MitM and DoS attacks, and unrelated parties might be		vulnerable to MitM and DoS attacks, and unrelated parties might be
	subject to DoS attacks as well. These threats are described in the		subject to DoS attacks as well. These threats are described in the
	following sections.		following sections.
	8.1 Attacker tampering with an unsecure HIPHI RR		8.1. Attacker tampering with an insecure HIPHI RR
	The HIPHI RR contains public keying material in the form of the named		The HIPHI RR contains public keying material in the form of the named
	peer's public key (the HI) and its secure hash (the HIT). Both of		peer's public key (the HI) and its secure hash (the HIT). Both of
	these are not sensitive to attacks where an adversary gains knowledge		these are not sensitive to attacks where an adversary gains knowledge
	of them. However, an attacker that is able to mount an active attack		of them. However, an attacker that is able to mount an active attack
	on the DNS, i.e., tampers with this HIPHI RR (e.g. using DNS		on the DNS, i.e., tampers with this HIPHI RR (e.g. using DNS
	spoofing) is able to mount Man-in-the-Middle attacks on the		spoofing) is able to mount Man-in-the-Middle attacks on the
	cryptographic core of the eventual HIP exchange (responder's HIPHI		cryptographic core of the eventual HIP exchange (responder's HIPHI
	and HIPRVS rewritten by the attacker).		and HIPRVS rewritten by the attacker).
	8.2 Attacker tampering with an unsecure HIPRVS RR		8.2. Attacker tampering with an insecure HIPRVS RR
	The HIPRVS RR contains a destination IP address where the named peer		The HIPRVS RR contains a destination IP address where the named peer
	is reachable by an I1 (HIP Rendezvous Extensions IPSECKEY RR [14] ).		is reachable by an I1 (HIP Rendezvous Extensions IPSECKEY RR
	Thus, an attacker able to tamper with this RRs is able to redirect I1		[I-D.ietf-hip-rvs] ). Thus, an attacker able to tamper with this RR
	packets sent to the named peer to a chosen IP address, for DoS or		is able to redirect I1 packets sent to the named peer to a chosen IP
	MitM attacks. Note that this kind of attacks are not specific to HIP		address, for DoS or MitM attacks. Note that this kind of attacks is
	and exist independently to whether or not HIP and the HIPRVS RR are		not specific to HIP and exists independently to whether or not HIP
	used. Such an attacker might tamper with A and AAAA RRs as well.		and the HIPRVS RR are used. Such an attacker might tamper with A and
			AAAA RRs as well.
	An attacker might obviously use these two attacks in conjunction: It		An attacker might obviously use these two attacks in conjunction: It
	will replace the responder's HI and RVS IP address by its owns in a		will replace the responder's HI and RVS IP address by its owns in a
	spoofed DNS packet sent to the initiator HI, then redirect all		spoofed DNS packet sent to the initiator HI, then redirect all
	exchanged packets through him and mount a MitM on HIP. In this case		exchanged packets to him and mount a MitM on HIP. In this case HIP
	HIP won't provide confidentiality nor initiator HI protection from		won't provide confidentiality nor initiator HI protection from
	eavesdroppers.		eavesdroppers.
	8.3 Opportunistic HIP		8.3. Opportunistic HIP
	A HIP initiator may not be aware of its peer's HI, and/or its HIT		A HIP initiator may not be aware of its peer's HI, and/or its HIT
	(e.g. because the DNS does not contains HIP material, or the resolver		(e.g. because the DNS does not contains HIP material, or the resolver
	isn't HIP-enabled), and attempt an opportunistic HIP exchange towards		isn't HIP-enabled), and attempt an opportunistic HIP exchange towards
	its known IP address, filling the responder HIT field with zeros in		its known IP address, filling the responder HIT field with zeros in
	the I1 header. Such an initiator is vulnerable to a MitM attack		the I1 header. Such an initiator is vulnerable to a MitM attack
	because it can't validate the HI and HIT contained in a replied R1.		because it can't validate the HI and HIT contained in a replied R1.
	Hence, an implementation MAY choose not to use opportunistic mode.		Hence, an implementation MAY choose not to use opportunistic mode.
	8.4 Unpublished Initiator HI		8.4. Unpublished Initiator HI
	A HIP initiator may choose to use an unpublished HI, which is not		A HIP initiator may choose to use an unpublished HI, which is not
	stored in the DNS by means of a HIPHI RR. A responder associating		stored in the DNS by means of a HIPHI RR. A responder associating
	with such an initiator knowingly risks a MitM attack because it		with such an initiator knowingly risks a MitM attack because it
	cannot validate the initiator's HI. Hence, an implementation MAY		cannot validate the initiator's HI. Hence, an implementation MAY
	choose not to use unpublished mode.		choose not to use unpublished mode.
	8.5 Hash and HITs Collisions		8.5. Hash and HITs Collisions
	As many cryptographic algorithm, some secure hashes (e.g. SHA1, used		As many cryptographic algorithm, some secure hashes (e.g. SHA1, used
	by HIP to generate a HIT from an HI) eventually become insecure,		by HIP to generate a HIT from an HI) eventually become insecure,
	because an exploit has been found in which an attacker with a		because an exploit has been found in which an attacker with a
	reasonable computation power breaks one of the security features of		reasonable computation power breaks one of the security features of
	the hash (e.g. its supposed collision resistance). This is why a HIP		the hash (e.g. its supposed collision resistance). This is why a HIP
	end-node implementation SHOULD NOT authenticate its HIP peers based		end-node implementation SHOULD NOT authenticate its HIP peers based
	solely on a HIT retrieved from DNS, but SHOULD rather use HI-based		solely on a HIT retrieved from DNS, but SHOULD rather use HI-based
	authentication.		authentication.
	8.6 DNSSEC		8.6. DNSSEC
	In the absence of DNSSEC, the HIPHI and HIPRVS RRs are subject to the		In the absence of DNSSEC, the HIPHI and HIPRVS RRs are subject to the
	threats described in RFC 3833 [17].		threats described in RFC 3833 [RFC3833].
	9. IANA Considerations		9. IANA Considerations
	IANA needs to allocate two new RR type code for HIPHI and HIPRVS from		IANA needs to allocate two new RR type code for HIPHI and HIPRVS from
	the standard RR type space.		the standard RR type space.
	IANA needs to open a new registry for the HIPHI RR HIT type. Defined
	types are:
	0 No HIT is present
	1 A Type 1 HIT is present
	2 A Type 2 HIT is present
	3-6 Unassigned
	7 A HAA is present
	Adding new reservations requires IETF consensus RFC2434 [16].
	IANA needs to open a new registry for the HIPHI RR HIT algorithm.
	Defined types are:
	0 Reserved
	1 SHA1
	2-255 Unassigned
	Adding new reservations requires IETF consensus RFC2434 [16].
	IANA does not need to open a new registry for the HIPHI RR type for		IANA does not need to open a new registry for the HIPHI RR type for
	public key algorithms because the HIPHI RR reuse 'algorithms types'		public key algorithms because the HIPHI RR reuse 'algorithms types'
	defined for the IPSECKEY RR [10]. The presently defined numbers are		defined for the IPSECKEY RR [RFC4025]. The presently defined numbers
	given here only informally:		are given here only informally:
	0 is reserved		0 is reserved
	1 is RSA		1 is RSA
	2 is DSA		2 is DSA
	IANA does not need to open a new registry for the HIPRVS RR		IANA does not need to open a new registry for the HIPRVS RR
	Rendezvous server type because the HIPHI RR reuse the 'gateway types'		rendezvous server type because the HIPHI RR reuse the 'gateway types'
	defined for the IPSECKEY RR [10]. The presently defined numbers are		defined for the IPSECKEY RR [RFC4025]. The presently defined numbers
	given here only informally:		are given here only informally:
	0 is reserved		0 is reserved
	1 is IPv4		1 is IPv4
	2 is IPv6		2 is IPv6
	3 is a wire-encoded uncompressed domain name		3 is a wire-encoded uncompressed domain name
	10. Acknowledgments		10. Acknowledgments
	As usual in the IETF, this document is the result of a collaboration		As usual in the IETF, this document is the result of a collaboration
	between many people. The authors would like to thanks the author		between many people. The authors would like to thanks the author
	(Michael Richardson), contributors and reviewers of the IPSECKEY RR		(Michael Richardson), contributors and reviewers of the IPSECKEY RR
	[10] specification, which this document was framed after. The		[RFC4025] specification, which this document was framed after. The
	authors would also like to thanks the following people, who have		authors would also like to thanks the following people, who have
	provided thoughtful and helpful discussions and/or suggestions, that		provided thoughtful and helpful discussions and/or suggestions, that
	have helped improving this document: Rob Austein, Hannu Flinck, Tom		have helped improving this document: Rob Austein, Hannu Flinck, Tom
	Henderson, Olaf Kolkman, Miika Komu, Andrew McGregor, Erik Nordmark,		Henderson, Olaf Kolkman, Miika Komu, Andrew McGregor, Erik Nordmark,
	and Gabriel Montenegro. Some parts of this draft stem from [11].		and Gabriel Montenegro. Some parts of this draft stem from
			[I-D.ietf-hip-base].
	Julien Laganier is partly funded by Ambient Networks, a research		Julien Laganier is partly funded by Ambient Networks, a research
	project supported by the European Commission under its Sixth		project supported by the European Commission under its Sixth
	Framework Program. The views and conclusions contained herein are		Framework Program. The views and conclusions contained herein are
	those of the authors and should not be interpreted as necessarily		those of the authors and should not be interpreted as necessarily
	representing the official policies or endorsements, either expressed		representing the official policies or endorsements, either expressed
	or implied, of the Ambient Networks project or the European		or implied, of the Ambient Networks project or the European
	Commission.		Commission.
	11. References		11. References
	11.1 Normative references		11.1. Normative references
	[1] Mockapetris, P., "Domain names - concepts and facilities",		[RFC1034] Mockapetris, P., "Domain names - concepts and facilities",
	STD 13, RFC 1034, November 1987.		STD 13, RFC 1034, November 1987.
	[2] Mockapetris, P., "Domain names - implementation and		[RFC1035] Mockapetris, P., "Domain names - implementation and
	specification", STD 13, RFC 1035, November 1987.		specification", STD 13, RFC 1035, November 1987.
	[3] Eastlake, D. and C. Kaufman, "Domain Name System Security		[RFC2065] Eastlake, D. and C. Kaufman, "Domain Name System Security
	Extensions", RFC 2065, January 1997.		Extensions", RFC 2065, January 1997.
	[4] Bradner, S., "Key words for use in RFCs to Indicate Requirement		[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
	Levels", BCP 14, RFC 2119, March 1997.		Requirement Levels", BCP 14, RFC 2119, March 1997.
	[5] Eastlake, D., "DSA KEYs and SIGs in the Domain Name System		[RFC2536] Eastlake, D., "DSA KEYs and SIGs in the Domain Name System
	(DNS)", RFC 2536, March 1999.		(DNS)", RFC 2536, March 1999.
	[6] Eastlake, D., "RSA/SHA-1 SIGs and RSA KEYs in the Domain Name		[RFC3110] Eastlake, D., "RSA/SHA-1 SIGs and RSA KEYs in the Domain
	System (DNS)", RFC 3110, May 2001.		Name System (DNS)", RFC 3110, May 2001.
	[7] Bush, R., Durand, A., Fink, B., Gudmundsson, O., and T. Hain,
	"Representing Internet Protocol version 6 (IPv6) Addresses in
	the Domain Name System (DNS)", RFC 3363, August 2002.
	[8] Josefsson, S., "The Base16, Base32, and Base64 Data Encodings",		[RFC3363] Bush, R., Durand, A., Fink, B., Gudmundsson, O., and T.
	RFC 3548, July 2003.		Hain, "Representing Internet Protocol version 6 (IPv6)
			Addresses in the Domain Name System (DNS)", RFC 3363,
			August 2002.
	[9] Thomson, S., Huitema, C., Ksinant, V., and M. Souissi, "DNS		[RFC3548] Josefsson, S., "The Base16, Base32, and Base64 Data
	Extensions to Support IP Version 6", RFC 3596, October 2003.		Encodings", RFC 3548, July 2003.
	[10] Richardson, M., "A Method for Storing IPsec Keying Material in		[RFC3596] Thomson, S., Huitema, C., Ksinant, V., and M. Souissi,
	DNS", RFC 4025, March 2005.		"DNS Extensions to Support IP Version 6", RFC 3596,
			October 2003.
	[11] Moskowitz, R., "Host Identity Protocol", draft-ietf-hip-base-03		[RFC4025] Richardson, M., "A Method for Storing IPsec Keying
	(work in progress), June 2005.		Material in DNS", RFC 4025, March 2005.
	[12] Moskowitz, R., "Host Identity Protocol Architecture",		[I-D.ietf-hip-base]
	draft-ietf-hip-arch-02 (work in progress), January 2005.		Moskowitz, R., "Host Identity Protocol",
			draft-ietf-hip-base-03 (work in progress), June 2005.
	[13] Nikander, P., "End-Host Mobility and Multi-Homing with Host		[I-D.ietf-hip-rvs]
	Identity Protocol", draft-ietf-hip-mm-01 (work in progress),		Laganier, J. and L. Eggert, "Host Identity Protocol (HIP)
	February 2005.		Rendezvous Extension", draft-ietf-hip-rvs-04 (work in
			progress), October 2005.
	[14] Laganier, J. and L. Eggert, "Host Identity Protocol (HIP)		11.2. Informative references
	Rendezvous Extension", draft-ietf-hip-rvs-02 (work in
	progress), June 2005.
	11.2 Informative references		[I-D.ietf-hip-arch]
			Moskowitz, R. and P. Nikander, "Host Identity Protocol
			Architecture", draft-ietf-hip-arch-03 (work in progress),
			August 2005.
	[15] Jokela, P., "Using ESP transport format with HIP",		[I-D.ietf-hip-mm]
	draft-jokela-hip-esp-00 (work in progress), February 2005.		Nikander, P., "End-Host Mobility and Multihoming with the
			Host Identity Protocol", draft-ietf-hip-mm-02 (work in
			progress), July 2005.
	[16] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA		[RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an
	Considerations Section in RFCs", BCP 26, RFC 2434,		IANA Considerations Section in RFCs", BCP 26, RFC 2434,
	October 1998.		October 1998.
	[17] Atkins, D. and R. Austein, "Threat Analysis of the Domain Name		[RFC3833] Atkins, D. and R. Austein, "Threat Analysis of the Domain
	System (DNS)", RFC 3833, August 2004.		Name System (DNS)", RFC 3833, August 2004.
	Authors' Addresses		Authors' Addresses
	Pekka Nikander		Pekka Nikander
	Ericsson Research Nomadic Lab		Ericsson Research Nomadic Lab
	JORVAS FIN-02420		JORVAS FIN-02420
	FINLAND		FINLAND
	Phone: +358 9 299 1		Phone: +358 9 299 1
	Email: pekka.nikander@nomadiclab.com		Email: pekka.nikander@nomadiclab.com
End of changes. 119 change blocks.
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