Split DNS Configuration for the Internet Key Exchange Protocol Version 2 (IKEv2)
RFC 8598
Internet Engineering Task Force (IETF) T. Pauly
Request for Comments: 8598 Apple Inc.
Category: Standards Track P. Wouters
ISSN: 2070-1721 Red Hat
May 2019
Split DNS Configuration
for the Internet Key Exchange Protocol Version 2 (IKEv2)
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-
tunnel configurations.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 7841.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc8598.
Pauly & Wouters Standards Track [Page 1]
RFC 8598 Split DNS Configuration for IKEv2 May 2019
Copyright Notice
Copyright (c) 2019 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
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publication of this document. Please review these documents
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 4
2. Applicability . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Protocol Exchange . . . . . . . . . . . . . . . . . . . . . . 5
3.1. Configuration Request . . . . . . . . . . . . . . . . . . 5
3.2. Configuration Reply . . . . . . . . . . . . . . . . . . . 6
3.3. Mapping DNS Servers to Domains . . . . . . . . . . . . . 7
3.4. Example Exchanges . . . . . . . . . . . . . . . . . . . . 7
3.4.1. Simple Case . . . . . . . . . . . . . . . . . . . . . 7
3.4.2. Requesting Domains and DNSSEC Trust Anchors . . . . . 7
4. Payload Formats . . . . . . . . . . . . . . . . . . . . . . . 9
4.1. INTERNAL_DNS_DOMAIN Configuration Attribute Type Request
and Reply . . . . . . . . . . . . . . . . . . . . . . . . 9
4.2. INTERNAL_DNSSEC_TA Configuration Attribute . . . . . . . 9
5. INTERNAL_DNS_DOMAIN Usage Guidelines . . . . . . . . . . . . 11
6. INTERNAL_DNSSEC_TA Usage Guidelines . . . . . . . . . . . . . 12
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13
8. Security Considerations . . . . . . . . . . . . . . . . . . . 14
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 15
9.1. Normative References . . . . . . . . . . . . . . . . . . 15
9.2. Informative References . . . . . . . . . . . . . . . . . 16
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 16
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RFC 8598 Split DNS Configuration for IKEv2 May 2019
1. Introduction
Split-tunnel Virtual Private Network (VPN) configurations only send
packets with a specific destination IP range, usually chosen from
[RFC1918], via the VPN. All other traffic is not sent via the VPN.
This allows an enterprise deployment to offer remote access VPN
services without needing to accept and forward all the non-
enterprise-related network traffic generated by their remote users.
Resources within the enterprise can be accessed by the user via the
VPN, while all other traffic generated by the user is not sent over
the VPN.
These internal resources tend to only have internal-only DNS names
and require the use of special internal-only DNS servers to get
resolved. Split DNS [RFC2775] is commonly configured as part of
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