< draft-ietf-ipsecme-split-dns-08.txt		draft-ietf-ipsecme-split-dns-09.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: December 20, 2018 Red Hat		Expires: January 19, 2019 Red Hat
	June 18, 2018		July 18, 2018
	Split DNS Configuration for IKEv2		Split DNS Configuration for IKEv2
	draft-ietf-ipsecme-split-dns-08		draft-ietf-ipsecme-split-dns-09
	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 http://datatracker.ietf.org/drafts/current/.		Drafts is at http://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 December 20, 2018.		This Internet-Draft will expire on January 19, 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
	(http://trustee.ietf.org/license-info) in effect on the date of		(http://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 25 ¶		skipping to change at page 2, line 25 ¶
	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 . . . . . . . . . . . . 9
	6. INTERNAL_DNSSEC_TA Usage Guidelines . . . . . . . . . . . . . 10		6. INTERNAL_DNSSEC_TA Usage Guidelines . . . . . . . . . . . . . 10
	7. Security Considerations . . . . . . . . . . . . . . . . . . . 10		7. Security Considerations . . . . . . . . . . . . . . . . . . . 11
	8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11		8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
	9. References . . . . . . . . . . . . . . . . . . . . . . . . . 12		9. References . . . . . . . . . . . . . . . . . . . . . . . . . 12
	9.1. Normative References . . . . . . . . . . . . . . . . . . 12		9.1. Normative References . . . . . . . . . . . . . . . . . . 12
	9.2. Informative References . . . . . . . . . . . . . . . . . 12		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
	[RFC2775]. In such configurations, it is often desirable to only		[RFC2775]. In such configurations, it is often desirable to only
	resolve hosts within a set of private domains using the tunnel, while		resolve hosts within a set of private domains using the tunnel, while
	letting resolutions for public hosts be handled by a device's default		letting resolutions for public hosts be handled by a device's default
	skipping to change at page 10, line 10 ¶		skipping to change at page 10, line 10 ¶
	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
	private remote network using the IPsec connection. If all traffic is		private remote network using the IPsec connection. If all traffic is
	routed over the IPsec connection, the existing global		routed over the IPsec connection, the existing global
	INTERNAL_IP4_DNS and INTERNAL_IP6_DNS can be used without creating		INTERNAL_IP4_DNS and INTERNAL_IP6_DNS can be used without creating
	specific DNS exemptions.		specific DNS exemptions.
	6. INTERNAL_DNSSEC_TA Usage Guidelines		6. INTERNAL_DNSSEC_TA Usage Guidelines
	Installing an INTERNAL_DNSSEC_TA trust anchor can be seen as the		DNS records can be used to publish specific records containing trust
	equivalent of installing an Enterprise Certificate Agency (CA)		anchors for applications. The most common record type is the TLSA
			record specified in [RFC6698]. This DNS record type publishes which
			CA certificate or EE certificate to expect for a certain host name.
			These records are protected by DNSSEC and thus can be trusted by the
			application. Whether to trust TLSA records instead of the
			traditional WebPKI depends on the local policy of the client. By
			accepting an INTERNAL_DNSSEC_TA trust anchor via IKE from the remote
			IKE server, the IPsec client might be allowing the remote IKE server
			to override the trusted certificates for TLS. Similar override
			concerns apply to other public key or fingerprint based DNS records,
			such as OPENPGPKEY, SMIMEA or IPSECKEY records.
			Thus, installing an INTERNAL_DNSSEC_TA trust anchor can be seen as
			the equivalent of installing an Enterprise Certificate Agency (CA)
	certificate. It allows the remote IKE/IPsec server to modify DNS		certificate. It allows the remote IKE/IPsec server to modify DNS
	answers including its DNSSEC cryptographic signatures by overriding		answers including its DNSSEC cryptographic signatures by overriding
	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 domain names for
			which it will allow INTERNAL_DNSSEC_TA updates.
			The DNS root zone (".") MUST NOT be whitelisted.
			Any updates to this whitelist of domain names MUST happen via
			explicit human interaction to prevent invisible installation of trust
			anchors.
			IKE clients SHOULD accept any INTERNAL_DNSSEC_TA updates for
			subdomain names of the whitelisted domain names. For example, if
			"example.net" is whitelisted, then INTERNAL_DNSSEC_TA received for
			"antartica.example.net" SHOULD be accepted.
			IKE clients MAY interpret an INTERNAL_DNSSEC_TA for domain that was
			not preconfigured as an indication that it needs to update its IKE
			configuration (out of band). The client MUST NOT use such a
			INTERNAL_DNSSEC_TA to reconfigure its local DNS settings.
	IKE clients MUST ignore any received INTERNAL_DNSSEC_TA requests for		IKE clients MUST ignore any received INTERNAL_DNSSEC_TA requests for
	a FDQN for which it did not receive and accept an INTERNAL_DNS_DOMAIN		a FDQN for which it did not receive and accept an INTERNAL_DNS_DOMAIN
	Configuration Payload.		Configuration Payload.
	DNS records can be used to publish specific records containing trust
	anchors for applications. The most common record type is the TLSA
	record specified in [RFC6698]. This DNS record type publishes which
	CA certificate or EE certificate to expect for a certain host name.
	These records are protected by DNSSEC and thus can be trusted by the
	application. Whether to trust TLSA records instead of the
	traditional WebPKI depends on the local policy of the client. By
	accepting an INTERNAL_DNSSEC_TA trust anchor via IKE from the remote
	IKE server, the IPsec client might be allowing the remote IKE server
	to override the trusted certificates for TLS. The same applies to
	other public key or fingerprint based DNS records, such as
	OPENPGPKEY, SMIMEA or IPSECKEY records.
	In most deployment scenario's, the IKE client has an expectation that		In most deployment scenario's, the IKE client has an expectation that
	it is connecting, using a split-network setup, to a specific		it is connecting, using a split-network setup, to a specific
	organisation or enterprise. A recommended policy would be to only		organisation or enterprise. A recommended policy would be to only
	accept INTERNAL_DNSSEC_TA directives from that organization's DNS		accept INTERNAL_DNSSEC_TA directives from that organization's DNS
	names. However, this might not be possible in all deployment		names. However, this might not be possible in all deployment
	scenarios, such as one where the IKE server is handing out a number		scenarios, such as one where the IKE server is handing out a number
	of domains that are not within one parent domain.		of domains that are not within one parent domain.
	7. Security Considerations		7. Security Considerations
End of changes. 8 change blocks.
	22 lines changed or deleted		41 lines changed or added
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