< draft-ietf-ipsecme-split-dns-10.txt		draft-ietf-ipsecme-split-dns-11.txt >
	Network T. Pauly		Network T. Pauly
	Internet-Draft Apple Inc.		Internet-Draft Apple Inc.
	Intended status: Standards Track P. Wouters		Intended status: Standards Track P. Wouters
	Expires: January 19, 2019 Red Hat		Expires: January 20, 2019 Red Hat
	July 18, 2018		July 19, 2018
	Split DNS Configuration for IKEv2		Split DNS Configuration for IKEv2
	draft-ietf-ipsecme-split-dns-10		draft-ietf-ipsecme-split-dns-11
	Abstract		Abstract
	This document defines two Configuration Payload Attribute Types for		This document defines two Configuration Payload Attribute Types for
	the IKEv2 protocol that add support for private DNS domains. These		the IKEv2 protocol that add support for private DNS domains. These
	domains are intended to be resolved using DNS servers reachable		domains are intended to be resolved using DNS servers reachable
	through an IPsec connection, while leaving all other DNS resolution		through an IPsec connection, while leaving all other DNS resolution
	unchanged. This approach of resolving a subset of domains using non-		unchanged. This approach of resolving a subset of domains using non-
	public DNS servers is referred to as "Split DNS".		public DNS servers is referred to as "Split DNS".
	skipping to change at page 1, line 36 ¶		skipping to change at page 1, line 36 ¶
	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 19, 2019.		This Internet-Draft will expire on January 20, 2019.
	Copyright Notice		Copyright Notice
	Copyright (c) 2018 IETF Trust and the persons identified as the		Copyright (c) 2018 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 23 ¶		skipping to change at page 2, line 23 ¶
	3.1. Configuration Request . . . . . . . . . . . . . . . . . . 4		3.1. Configuration Request . . . . . . . . . . . . . . . . . . 4
	3.2. Configuration Reply . . . . . . . . . . . . . . . . . . . 4		3.2. Configuration Reply . . . . . . . . . . . . . . . . . . . 4
	3.3. Mapping DNS Servers to Domains . . . . . . . . . . . . . 5		3.3. Mapping DNS Servers to Domains . . . . . . . . . . . . . 5
	3.4. Example Exchanges . . . . . . . . . . . . . . . . . . . . 5		3.4. Example Exchanges . . . . . . . . . . . . . . . . . . . . 5
	3.4.1. Simple Case . . . . . . . . . . . . . . . . . . . . . 5		3.4.1. Simple Case . . . . . . . . . . . . . . . . . . . . . 5
	3.4.2. Requesting Domains and DNSSEC trust anchors . . . . . 6		3.4.2. Requesting Domains and DNSSEC trust anchors . . . . . 6
	4. Payload Formats . . . . . . . . . . . . . . . . . . . . . . . 6		4. Payload Formats . . . . . . . . . . . . . . . . . . . . . . . 6
	4.1. INTERNAL_DNS_DOMAIN Configuration Attribute Type Request		4.1. INTERNAL_DNS_DOMAIN Configuration Attribute Type Request
	and Reply . . . . . . . . . . . . . . . . . . . . . . . . 7		and Reply . . . . . . . . . . . . . . . . . . . . . . . . 7
	4.2. INTERNAL_DNSSEC_TA Configuration Attribute . . . . . . . 7		4.2. INTERNAL_DNSSEC_TA Configuration Attribute . . . . . . . 7
	5. INTERNAL_DNS_DOMAIN Usage Guidelines . . . . . . . . . . . . 9		5. INTERNAL_DNS_DOMAIN Usage Guidelines . . . . . . . . . . . . 8
	6. INTERNAL_DNSSEC_TA Usage Guidelines . . . . . . . . . . . . . 10		6. INTERNAL_DNSSEC_TA Usage Guidelines . . . . . . . . . . . . . 9
	7. Security Considerations . . . . . . . . . . . . . . . . . . . 11		7. Security Considerations . . . . . . . . . . . . . . . . . . . 11
	8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12		8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
	9. References . . . . . . . . . . . . . . . . . . . . . . . . . 12		9. References . . . . . . . . . . . . . . . . . . . . . . . . . 12
	9.1. Normative References . . . . . . . . . . . . . . . . . . 12		9.1. Normative References . . . . . . . . . . . . . . . . . . 12
	9.2. Informative References . . . . . . . . . . . . . . . . . 13		9.2. Informative References . . . . . . . . . . . . . . . . . 13
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13
	1. Introduction		1. Introduction
	Split DNS is a common configuration for secure tunnels, such as		Split DNS is a common configuration for secure tunnels, such as
	Virtual Private Networks in which host machines private to an		Virtual Private Networks in which host machines private to an
	organization can only be resolved using internal DNS resolvers		organization can only be resolved using internal DNS resolvers
	skipping to change at page 3, line 37 ¶		skipping to change at page 3, line 37 ¶
	The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",		The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
	"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and		"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
	"OPTIONAL" in this document are to be interpreted as described in BCP		"OPTIONAL" in this document are to be interpreted as described in BCP
	14 [RFC2119] [RFC8174] when, and only when, they appear in all		14 [RFC2119] [RFC8174] when, and only when, they appear in all
	captials, as shown here.		captials, as shown here.
	2. Background		2. Background
	Split DNS is a common configuration for enterprise VPN deployments,		Split DNS is a common configuration for enterprise VPN deployments,
	in which only one or a few private DNS domains are accessible and		in which one or more private DNS domains are only accessible and
	resolvable via an IPsec based VPN connection.		resolvable via an IPsec based VPN connection.
	Other tunnel-establishment protocols already support the assignment		Other tunnel-establishment protocols already support the assignment
	of Split DNS domains. For example, there are proprietary extensions		of Split DNS domains. For example, there are proprietary extensions
	to IKEv1 that allow a server to assign Split DNS domains to a client.		to IKEv1 that allow a server to assign Split DNS domains to a client.
	However, the IKEv2 standard does not include a method to configure		However, the IKEv2 standard does not include a method to configure
	this option. This document defines a standard way to negotiate this		this option. This document defines a standard way to negotiate this
	option for IKEv2.		option for IKEv2.
	3. Protocol Exchange		3. Protocol Exchange
	skipping to change at page 8, line 13 ¶		skipping to change at page 7, line 44 ¶
	fields.		fields.
	An empty INTERNAL_DNSSEC_TA CFG attribute:		An empty INTERNAL_DNSSEC_TA CFG attribute:
	1 2 3		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
	+-+-----------------------------+-------------------------------+		+-+-----------------------------+-------------------------------+
	|R| Attribute Type | Length (set to 0) |		|R| Attribute Type | Length (set to 0) |
	+-+-----------------------------+-------------------------------+		+-+-----------------------------+-------------------------------+
			o Reserved (1 bit) - Defined in IKEv2 RFC [RFC7296].
			o Attribute Type (15 bits) set to value 26 for INTERNAL_DNSSEC_TA.
			o Length (2 octets) - Set to 0 for an empty attribute.
	A non-empty INTERNAL_DNSSEC_TA CFG attribute:		A non-empty INTERNAL_DNSSEC_TA CFG attribute:
	1 2 3		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
	+-+-----------------------------+-------------------------------+		+-+-----------------------------+-------------------------------+
	|R| Attribute Type | Length |		|R| Attribute Type | Length |
	+-+-----------------------------+---------------+---------------+		+-+-----------------------------+---------------+---------------+
	| DNSKEY Key Tag | DNSKEY Alg | Digest Type |		| DNSKEY Key Tag | DNSKEY Alg | Digest Type |
	+-------------------------------+---------------+---------------+		+-------------------------------+---------------+---------------+
	| |		| |
	~ Digest Data ~		~ Digest Data ~
	| |		| |
	+---------------------------------------------------------------+		+---------------------------------------------------------------+
	o Reserved (1 bit) - Defined in IKEv2 RFC [RFC7296].		o Reserved (1 bit) - Defined in IKEv2 RFC [RFC7296].
	o Attribute Type (15 bits) set to value 26 for INTERNAL_DNSSEC_TA.		o Attribute Type (15 bits) set to value 26 for INTERNAL_DNSSEC_TA.
	o Length (0 or 2 octets) - Length of DNSSEC Trust Anchor data (4		o Length (2 octets) - Length of DNSSEC Trust Anchor data (4 octets
	octets plus the length of the Digest Data).		plus the length of the Digest Data).
	o DNSKEY Key Tag value (0 or 2 octets) - Delegation Signer (DS) Key		o DNSKEY Key Tag value (2 octets) - Delegation Signer (DS) Key Tag
	Tag as specified in [RFC4034] Section 5.1.		as specified in [RFC4034] Section 5.1.
	o DNSKEY Algorithm (0 or 1 octet) - DNSKEY algorithm value from the		o DNSKEY Algorithm (1 octet) - DNSKEY algorithm value from the IANA
	IANA DNS Security Algorithm Numbers Registry.		DNS Security Algorithm Numbers Registry.
	o Digest Type (0 or 1 octet) - DS algorithm value from the IANA		o Digest Type (1 octet) - DS algorithm value from the IANA
	Delegation Signer (DS) Resource Record (RR) Type Digest Algorithms		Delegation Signer (DS) Resource Record (RR) Type Digest Algorithms
	Registry.		Registry.
	o Digest Data (0 or more octets) - The DNSKEY digest as specified in		o Digest Data (1 or more octets) - The DNSKEY digest as specified in
	[RFC4034] Section 5.1 in presentation format.		[RFC4034] Section 5.1 in presentation format.
	INTERNAL_DNSSEC_TA payloads MUST immediately follow an		Each INTERNAL_DNSSEC_TA attribute in the CFG_REPLY payload MUST
	INTERNAL_DNS_DOMAIN payload. As the INTERNAL_DNSSEC_TA format itself		immediately follow a corresponding INTERNAL_DNS_DOMAIN attribute. As
	does not contain the domain name, it relies on the preceding		the INTERNAL_DNSSEC_TA format itself does not contain the domain
	INTERNAL_DNS_DOMAIN to provide the domain for which it specifies the		name, it relies on the preceding INTERNAL_DNS_DOMAIN to provide the
	trust anchor.		domain for which it specifies the trust anchor. Any
			INTERNAL_DNSSEC_TA attribute that is not immediately preceded by an
			INTERNAL_DNS_DOMAIN attribute MUST be ignored and treated as a
			protocol error.
	5. INTERNAL_DNS_DOMAIN Usage Guidelines		5. INTERNAL_DNS_DOMAIN Usage Guidelines
	If a CFG_REPLY payload contains no INTERNAL_DNS_DOMAIN attributes,		If a CFG_REPLY payload contains no INTERNAL_DNS_DOMAIN attributes,
	the client MAY use the provided INTERNAL_IP4_DNS or INTERNAL_IP6_DNS		the client MAY use the provided INTERNAL_IP4_DNS or INTERNAL_IP6_DNS
	servers as the default DNS server(s) for all queries.		servers as the default DNS server(s) for all queries.
	If a client is configured by local policy to only accept a limited		If a client is configured by local policy to only accept a limited
	number of INTERNAL_DNS_DOMAIN values, the client MUST ignore any		number of INTERNAL_DNS_DOMAIN values, the client MUST ignore any
	other INTERNAL_DNS_DOMAIN values.		other INTERNAL_DNS_DOMAIN values.
	For each INTERNAL_DNS_DOMAIN entry in a CFG_REPLY payload that is not		For each INTERNAL_DNS_DOMAIN entry in a CFG_REPLY payload that is not
	prohibited by local policy, the client MUST use the provided		prohibited by local policy, the client MUST use the provided
	INTERNAL_IP4_DNS or INTERNAL_IP6_DNS DNS servers as the only		INTERNAL_IP4_DNS or INTERNAL_IP6_DNS DNS servers as the only
	resolvers for the listed domains and its sub-domains and it MUST NOT		resolvers for the listed domains and its sub-domains and it MUST NOT
	attempt to resolve the provided DNS domains using its external DNS		attempt to resolve the provided DNS domains using its external DNS
	servers.		servers. Other domain names SHOULD be resolved using some other
			external DNS resolver(s), configured independently from IKE. Queries
	If the initiator host is configured to block DNS answers containing		for these other domains MAY be sent to the internal DNS resolver(s)
	IP addresses from special IP address ranges such as those of		listed in that CFG_REPLY message, but have no guarantee of being
	[RFC1918], the initiator SHOULD allow the DNS domains listed in the		answered. For example, if the INTERNAL_DNS_DOMAIN attribute
	INTERNAL_DNS_DOMAIN attributes to contain those Special IP addresses.		specifies "example.com", then "example.com", "www.example.com" and
			"mail.eng.example.com" MUST be resolved using the internal DNS
			resolver(s), but "anotherexample.com" and "ample.com" SHOULD NOT be
			resolved using the internal resolver and SHOULD use the system's
			external DNS resolver(s).
	If a CFG_REPLY contains one or more INTERNAL_DNS_DOMAIN attributes		The initiator SHOULD allow the DNS domains listed in the
	and its local policy does not forbid these values, the client MUST		INTERNAL_DNS_DOMAIN attributes to resolve to special IP address
	configure its DNS resolver to resolve those domains and all their		ranges, such as those of [RFC1918], even if the initiator host is
	subdomains using only the DNS resolver(s) listed in that CFG_REPLY		otherwise configured to block DNS answer containing these special IP
	message. If those resolvers fail, those names MUST NOT be resolved		addresses.
	using any other DNS resolvers. Other domain names SHOULD be resolved
	using some other external DNS resolver(s), configured independently
	from IKE. Queries for these other domains MAY be sent to the
	internal DNS resolver(s) listed in that CFG_REPLY message, but have
	no guarantee of being answered. For example, if the
	INTERNAL_DNS_DOMAIN attribute specifies "example.com", then
	"example.com", "www.example.com" and "mail.eng.example.com" MUST be
	resolved using the internal DNS resolver(s), but "anotherexample.com"
	and "ample.com" SHOULD NOT be resolved using the internal resolver
	and SHOULD use the system's external DNS resolver(s).
	When an IKE SA is terminated, the DNS forwarding MUST be		When an IKE SA is terminated, the DNS forwarding MUST be
	unconfigured. This includes deleting the DNS forwarding rules;		unconfigured. This includes deleting the DNS forwarding rules;
	flushing all cached data for DNS domains provided by the		flushing all cached data for DNS domains provided by the
	INTERNAL_DNS_DOMAIN attribute, including negative cache entries;		INTERNAL_DNS_DOMAIN attribute, including negative cache entries;
	removing any obtained DNSSEC trust anchors from the list of trust		removing any obtained DNSSEC trust anchors from the list of trust
	anchors; and clearing the outstanding DNS request queue.		anchors; and clearing the outstanding DNS request queue.
	INTERNAL_DNS_DOMAIN attributes SHOULD only be used on split tunnel		INTERNAL_DNS_DOMAIN attributes SHOULD only be used on split tunnel
	configurations where only a subset of traffic is routed into a		configurations where only a subset of traffic is routed into a
	skipping to change at page 10, line 37 ¶		skipping to change at page 10, line 25 ¶
	existing DNS information with trust anchor conveyed via IKE and		existing DNS information with trust anchor conveyed via IKE and
	(temporarilly) installed on the IKE client. Of specific concern is		(temporarilly) installed on the IKE client. Of specific concern is
	the overriding of [RFC6698] based TLSA records, which represent a		the overriding of [RFC6698] based TLSA records, which represent a
	confirmation or override of an existing WebPKI TLS certificate.		confirmation or override of an existing WebPKI TLS certificate.
	Other DNS record types that convey cryptographic materials (public		Other DNS record types that convey cryptographic materials (public
	keys or fingerprints) are OPENPGPKEY, SMIMEA, SSHP and IPSECKEY		keys or fingerprints) are OPENPGPKEY, SMIMEA, SSHP and IPSECKEY
	records.		records.
	IKE clients MUST use a preconfigured whitelist of one or more domain		IKE clients MUST use a preconfigured whitelist of one or more domain
	names for which it will allow INTERNAL_DNSSEC_TA updates. This list		names for which it will allow INTERNAL_DNSSEC_TA updates. This list
	may be sent in the CFG_REQUEST payload, or may be applied after		can either be sent in the CFG_REQUEST payload, or else be applied
	reception of the CFG_REPLY payload.		after reception of the CFG_REPLY payload.
	IKE clients should take care to only whitelist domains that apply to		IKE clients should take care to only whitelist domains that apply to
	internal or managed domains, rather than to generic Internet traffic.		internal or managed domains, rather than to generic Internet traffic.
	The DNS root zone (".") MUST NOT be whitelisted. Other generic or		The DNS root zone (".") MUST NOT be whitelisted. Other generic or
	public domains, such as top-level domains, similarly SHOULD NOT be		public domains, such as top-level domains, similarly SHOULD NOT be
	whitelisted.		whitelisted.
	Any updates to this whitelist of domain names MUST happen via		Any updates to this whitelist of domain names MUST happen via
	explicit human interaction to prevent invisible installation of trust		explicit human interaction to prevent invisible installation of trust
	anchors.		anchors.
End of changes. 16 change blocks.
	44 lines changed or deleted		47 lines changed or added
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