Nameservers for IPv4 and IPv6 Reverse Zones
RFC 5855

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

• Versions
• 01

Internet Engineering Task Force (IETF)                          J. Abley
Request for Comments: 5855                                  T. Manderson
BCP: 155                                                           ICANN
Category: Best Current Practice                                 May 2010
ISSN: 2070-1721

              Nameservers for IPv4 and IPv6 Reverse Zones

Abstract

   This document specifies a stable naming scheme for the nameservers
   that serve the zones IN-ADDR.ARPA and IP6.ARPA in the DNS.  These
   zones contain data that facilitate reverse mapping (address to name).

Status of This Memo

   This memo documents an Internet Best Current Practice.

   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
   BCPs 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/rfc5855.

Copyright Notice

   Copyright (c) 2010 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.

Abley & Manderson         Best Current Practice                 [Page 1]
RFC 5855              Nameservers for Reverse Zones             May 2010

Table of Contents

   1. Introduction ....................................................2
   2. Nameservers for IN-ADDR.ARPA ....................................3
   3. Nameservers for IP6.ARPA ........................................3
   4. IAB Statement ...................................................4
   5. IANA Considerations .............................................4
   6. Security Considerations .........................................4
   7. References ......................................................4
      7.1. Normative References .......................................4
      7.2. Informative References .....................................5
   Appendix A.  Existing NS RRSets ....................................6
   Appendix B.  Performance Characteristics ...........................7
     B.1.  Label Compression ..........................................7
     B.2.  Query Patterns .............................................9
       B.2.1.  QNAME under IN-ADDR.ARPA ..............................10
       B.2.2.  QNAME under IP6.ARPA ..................................10

1.  Introduction

   The Domain Name System (DNS) is described in [RFC1034] and [RFC1035].
   The DNS currently supports keyed data retrieval using three
   namespaces -- domain names, IPv4 addresses, and IPv6 addresses.
   Mapping of IPv4 addresses to names is accomplished using data
   published in the IN-ADDR.ARPA zone.  For IPv6, the IP6.ARPA zone is
   used (see [RFC3596]).  The process of mapping an address to a name is
   generally known as a "reverse lookup", and the IN-ADDR.ARPA and
   IP6.ARPA zones are said to support the "reverse DNS".

   The secure and stable hosting of the IN-ADDR.ARPA and IP6.ARPA zones
   is critical to the operation of the Internet, since many applications
   rely upon timely responses to reverse lookups to be able to operate
   normally.

   At the time of this writing, the IN-ADDR.ARPA zone is served by a
   subset of the DNS root servers, and IP6.ARPA by servers operated by
   APNIC, ARIN, ICANN, LACNIC, and the RIPE NCC (see Appendix A).

   This document specifies a dedicated and stable set of nameserver
   names for each of the IN-ADDR.ARPA and IP6.ARPA zones.

   The naming scheme specified in this document allows IN-ADDR.ARPA and
   IP6.ARPA to be delegated to two different sets of nameservers, to
   facilitate operational separation of the infrastructure used to serve
   each zone.  This separation might help ensure that an operational
   failure of IN-ADDR.ARPA servers does not impact IPv6 reverse lookups
   as collateral damage, for example.

Abley & Manderson         Best Current Practice                 [Page 2]
RFC 5855              Nameservers for Reverse Zones             May 2010

   The choice of operators for individual nameservers is beyond the
   scope of this document and is an IANA function that falls under the
   scope of Section 4 of the Memorandum of Understanding (MoU) between