RFC 6147 - DNS64: DNS Extensions for Network Address Translation from IPv6 Clients to IPv4 Servers

• Status: Proposed Standard
• Published: April 2011
• Stream: IETF
• Errata: RFC Editor Errata

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Abstract

DNS64 is a mechanism for synthesizing AAAA records from A records. DNS64 is used with an IPv6/IPv4 translator to enable client-server communication between an IPv6-only client and an IPv4-only server, without requiring any changes to either the IPv6 or the IPv4 node, for the class of applications that work through NATs. This document specifies DNS64, and provides suggestions on how it should be deployed in conjunction with IPv6/IPv4 translators.

Table of Contents

• 1. Introduction
• 2. Overview
• 3. Background to DNS64-DNSSEC Interaction
• 4. Terminology
• 5. DNS64 Normative Specification
  • 5.1. Resolving AAAA Queries and the Answer Section
    • 5.1.1. The Answer when There is AAAA Data Available
    • 5.1.2. The Answer when There is an Error
    • 5.1.3. Dealing with Timeouts
    • 5.1.4. Special Exclusion Set for AAAA Records
    • 5.1.5. Dealing with CNAME and DNAME
    • 5.1.6. Data for the Answer when Performing Synthesis
    • 5.1.7. Performing the Synthesis
    • 5.1.8. Querying in Parallel
  • 5.2. Generation of the IPv6 Representations of IPv4 Addresses
  • 5.3. Handling Other Resource Records and the Additional Section
    • 5.3.1. PTR Resource Record
    • 5.3.2. Handling the Additional Section
    • 5.3.3. Other Resource Records
  • 5.4. Assembling a Synthesized Response to a AAAA Query
  • 5.5. DNSSEC Processing: DNS64 in Validating Resolver Mode
• 6. Deployment Notes
  • 6.1. DNS Resolvers and DNS64
  • 6.2. DNSSEC Validators and DNS64
  • 6.3. DNS64 and Multihomed and Dual-Stack Hosts
    • 6.3.1. IPv6 Multihomed Hosts
    • 6.3.2. Accidental Dual-Stack DNS64 Use
    • 6.3.3. Intentional Dual-Stack DNS64 Use
• 7. Deployment Scenarios and Examples
  • 7.1. Example of "an IPv6 Network to the IPv4 Internet" Setup with DNS64 in DNS Server Mode
  • 7.2. Example of "an IPv6 Network to the IPv4 Internet" Setup with DNS64 in Stub-Resolver Mode
  • 7.3. Example of "the IPv6 Internet to an IPv4 Network" Setup with DNS64 in DNS Server Mode
• 8. Security Considerations
• 9. Contributors
• 10. Acknowledgements
• 11. References
  • 11.1. Normative References
  • 11.2. Informative References
• Appendix A. Motivations and Implications of Synthesizing AAAA Resource Records when Real AAAA Resource Records Exist
• Authors' Addresses

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 5741.

Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc6147.

Copyright Notice

Copyright (c) 2011 IETF Trust and the persons identified as the document authors. All rights reserved.

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