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

• Status
• IESG evaluation record
• IESG writeups
• Email expansions
• History

• Versions
• 11

Internet Engineering Task Force (IETF)                        M. Bagnulo
Request for Comments: 6147                                          UC3M
Category: Standards Track                                    A. Sullivan
ISSN: 2070-1721                                                 Shinkuro
                                                             P. Matthews
                                                          Alcatel-Lucent
                                                          I. van Beijnum
                                                          IMDEA Networks
                                                              April 2011

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

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.

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.

Bagnulo, et al.              Standards Track                    [Page 1]
RFC 6147                          DNS64                       April 2011

Copyright Notice

   Copyright (c) 2011 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
   carefully, as they describe your rights and restrictions with respect
   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.

Bagnulo, et al.              Standards Track                    [Page 2]
RFC 6147                          DNS64                       April 2011

Table of Contents

   1. Introduction ....................................................4
   2. Overview ........................................................5
   3. Background to DNS64-DNSSEC Interaction ..........................7
   4. Terminology .....................................................9
   5. DNS64 Normative Specification ..................................10
      5.1. Resolving AAAA Queries and the Answer Section .............11
           5.1.1. The Answer when There is AAAA Data Available .......11
           5.1.2. The Answer when There is an Error ..................11
           5.1.3. Dealing with Timeouts ..............................12
           5.1.4. Special Exclusion Set for AAAA Records .............12
           5.1.5. Dealing with CNAME and DNAME .......................12
           5.1.6. Data for the Answer when Performing Synthesis ......13
           5.1.7. Performing the Synthesis ...........................13
           5.1.8. Querying in Parallel ...............................14
      5.2. Generation of the IPv6 Representations of IPv4 Addresses ..14
      5.3. Handling Other Resource Records and the Additional
           Section ...................................................15
           5.3.1. PTR Resource Record ................................15
           5.3.2. Handling the Additional Section ....................16
           5.3.3. Other Resource Records .............................17
      5.4. Assembling a Synthesized Response to a AAAA Query .........17
      5.5. DNSSEC Processing: DNS64 in Validating Resolver Mode ......17
   6. Deployment Notes ...............................................19
      6.1. DNS Resolvers and DNS64 ...................................19
      6.2. DNSSEC Validators and DNS64 ...............................19
      6.3. DNS64 and Multihomed and Dual-Stack Hosts .................19
           6.3.1. IPv6 Multihomed Hosts ..............................19
           6.3.2. Accidental Dual-Stack DNS64 Use ....................20
           6.3.3. Intentional Dual-Stack DNS64 Use ...................21