--- 1/draft-ietf-ipsecme-split-dns-15.txt 2018-11-25 23:13:22.112221949 -0800 +++ 2/draft-ietf-ipsecme-split-dns-16.txt 2018-11-25 23:13:22.148222810 -0800 @@ -1,19 +1,19 @@ Network T. Pauly Internet-Draft Apple Inc. Intended status: Standards Track P. Wouters -Expires: May 26, 2019 Red Hat - November 22, 2018 +Expires: May 30, 2019 Red Hat + November 26, 2018 Split DNS Configuration for IKEv2 - draft-ietf-ipsecme-split-dns-15 + draft-ietf-ipsecme-split-dns-16 Abstract This document defines two Configuration Payload Attribute Types (INTERNAL_DNS_DOMAIN and INTERNAL_DNSSEC_TA) for the Internet Key Exchange Protocol Version 2 (IKEv2). These payloads add support for private (internal-only) DNS domains. These domains are intended to be resolved using non-public DNS servers that are only reachable through the IPsec connection. DNS resolution for other domains remains unchanged. These Configuration Payloads only apply to split @@ -27,21 +27,21 @@ Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." - This Internet-Draft will expire on May 26, 2019. + This Internet-Draft will expire on May 30, 2019. Copyright Notice Copyright (c) 2018 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents @@ -49,21 +49,21 @@ to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3 2. Applicability . . . . . . . . . . . . . . . . . . . . . . . . 3 - 3. Protocol Exchange . . . . . . . . . . . . . . . . . . . . . . 4 + 3. Protocol Exchange . . . . . . . . . . . . . . . . . . . . . . 5 3.1. Configuration Request . . . . . . . . . . . . . . . . . . 5 3.2. Configuration Reply . . . . . . . . . . . . . . . . . . . 5 3.3. Mapping DNS Servers to Domains . . . . . . . . . . . . . 6 3.4. Example Exchanges . . . . . . . . . . . . . . . . . . . . 6 3.4.1. Simple Case . . . . . . . . . . . . . . . . . . . . . 6 3.4.2. Requesting Domains and DNSSEC trust anchors . . . . . 7 4. Payload Formats . . . . . . . . . . . . . . . . . . . . . . . 7 4.1. INTERNAL_DNS_DOMAIN Configuration Attribute Type Request and Reply . . . . . . . . . . . . . . . . . . . . . . . . 8 4.2. INTERNAL_DNSSEC_TA Configuration Attribute . . . . . . . 8 @@ -93,22 +93,23 @@ of split tunnel VPN configurations to support configuring Remote Access users to use these special internal-only domain names. The IKEv2 protocol [RFC7296] negotiates configuration parameters using Configuration Payload Attribute Types. This document defines two Configuration Payload Attribute Types that add support for trusted Split DNS domains. The INTERNAL_DNS_DOMAIN attribute type is used to convey that the specified DNS domain MUST be resolved using the provided DNS - nameserver IP addresses, causing these requests to use the IPsec - connection. + nameserver IP addresses as specified in the INTERNAL_IP4_DNS and + INTERNAL_IP6_DNS Configuration Payloads, causing these requests to + use the IPsec connection. The INTERNAL_DNSSEC_TA attribute type is used to convey a DNSSEC trust anchor for such a domain. This is required if the external view uses DNSSEC that would prove the internal view does not exist or would expect a different DNSSEC key on the different versions (internal and external) of the enterprise domain. If an INTERNAL_DNS_DOMAIN is sent by the responder, the responder MUST also include one or more INTERNAL_IP4_DNS or INTERNAL_IP6_DNS attributes that contain the IPv4 or IPv6 address of the internal DNS @@ -168,22 +169,28 @@ configured for the enterprise DNS domains which removes the legal and technical responsibility of the enterprise to resolve every DNS domain potentially asked for by the remote user. A client using these configuration payloads will be able to request and receive Split DNS configurations using the INTERNAL_DNS_DOMAIN and INTERNAL_DNSSEC_TA configuration attributes. These attributes MUST be accompanied by one or more INTERNAL_IP4_DNS or INTERNAL_IP6_DNS configuration attributes. The client device can then use the internal DNS server(s) for any DNS queries within the - assigned domains. DNS queries for other domains MUST be sent to the - regular DNS service of the client. + assigned domains. DNS queries for other domains SHOULD be sent to + the regular DNS service of the client unless it prefers to use the + IPsec tunnel for all its DNS queries. For example, the client could + trust the IPsec provided DNS servers more than the locally provided + DNS servers especially in the case of connecting to unknown or + untrusted networks (eg coffee shops or hotel networks). Or the + client could prefer the IPsec based DNS servers because those provide + additional features over the local DNS servers. 3. Protocol Exchange In order to negotiate which domains are considered internal to an IKEv2 tunnel, initiators indicate support for Split DNS in their CFG_REQUEST payloads, and responders assign internal domains (and DNSSEC trust anchors) in their CFG_REPLY payloads. When Split DNS has been negotiated, the existing DNS server configuration attributes will be interpreted as internal DNS servers that can resolve hostnames within the internal domains. @@ -238,24 +245,23 @@ Each INTERNAL_DNS_DOMAIN represents a domain that the DNS servers address listed in INTERNAL_IP4_DNS and INTERNAL_IP6_DNS can resolve. If the CFG_REQUEST included INTERNAL_DNS_DOMAIN attributes with non- zero lengths, the content MAY be ignored or be interpreted as a suggestion by the responder. For each DNS domain specified in an INTERNAL_DNS_DOMAIN attribute, one or more INTERNAL_DNSSEC_TA attributes MAY be included by the responder. This attribute lists the corresponding internal DNSSEC - trust anchor in the DNS presentation format of a DS record as - specified in [RFC4034]. The INTERNAL_DNSSEC_TA attribute MUST - immediately follow the INTERNAL_DNS_DOMAIN attribute that it applies - to. + trust anchor information of a DS record (see [RFC4034]). The + INTERNAL_DNSSEC_TA attribute MUST immediately follow the + INTERNAL_DNS_DOMAIN attribute that it applies to. 3.3. Mapping DNS Servers to Domains All DNS servers provided in the CFG_REPLY MUST support resolving hostnames within all INTERNAL_DNS_DOMAIN domains. In other words, the INTERNAL_DNS_DOMAIN attributes in a CFG_REPLY payload form a single list of Split DNS domains that applies to the entire list of INTERNAL_IP4_DNS and INTERNAL_IP6_DNS attributes. 3.4. Example Exchanges @@ -335,21 +341,21 @@ +---------------------------------------------------------------+ o Reserved (1 bit) - Defined in IKEv2 RFC [RFC7296]. o Attribute Type (15 bits) set to value 25 for INTERNAL_DNS_DOMAIN. o Length (2 octets) - Length of domain name. o Domain Name (0 or more octets) - A Fully Qualified Domain Name used for Split DNS rules, such as "example.com", in DNS - presentation format and optionally using IDNA [RFC5890] for + presentation format and using IDNA A-label [RFC5890] for Internationalized Domain Names. Implementors need to be careful that this value is not null-terminated. 4.2. INTERNAL_DNSSEC_TA Configuration Attribute An INTERNAL_DNSSEC_TA Configuration Attribute can either be empty, or it can contain one Trust Anchor by containing a non-zero Length with a DNSKEY Key Tag, DNSKEY Algorithm, Digest Type and Digest Data fields.