RFC 2874 (rfc2874) - Page 2 of 20

DNS Extensions to Support IPv6 Address Aggregation and Renumbering

RFC 2874                        IPv6 DNS                       July 2000


Table of Contents

   1.  Introduction ...............................................  2
   2.  Overview ...................................................  3
       2.1.  Name-to-Address Lookup ...............................  4
       2.2.  Underlying Mechanisms for Reverse Lookups ............  4
           2.2.1.  Delegation on Arbitrary Boundaries .............  4
           2.2.2.  Reusable Zones .................................  5
   3.  Specifications .............................................  5
       3.1.  The A6 Record Type ...................................  5
           3.1.1.  Format .........................................  6
           3.1.2.  Processing .....................................  6
           3.1.3.  Textual Representation .........................  7
           3.1.4.  Name Resolution Procedure ......................  7
       3.2.  Zone Structure for Reverse Lookups ...................  7
   4.  Modifications to Existing Query Types ......................  8
   5.  Usage Illustrations ........................................  8
       5.1.  A6 Record Chains .....................................  9
           5.1.1.  Authoritative Data .............................  9
           5.1.2.  Glue ........................................... 10
           5.1.3.  Variations ..................................... 12
       5.2.  Reverse Mapping Zones ................................ 13
           5.2.1.  The TLA level .................................. 13
           5.2.2.  The ISP level .................................. 13
           5.2.3.  The Site Level ................................. 13
       5.3.  Lookups .............................................. 14
       5.4.  Operational Note ..................................... 15
   6.  Transition from RFC 1886 and Deployment Notes .............. 15
       6.1.  Transition from AAAA and Coexistence with A Records .. 16
       6.2.  Transition from Nibble Labels to Binary Labels ....... 17
   7.  Security Considerations .................................... 17
   8.  IANA Considerations ........................................ 17
   9.  Acknowledgments ............................................ 18
   10.  References ................................................ 18
   11.  Authors' Addresses ........................................ 19
   12.  Full Copyright Statement .................................. 20

1.  Introduction

   Maintenance of address information in the DNS is one of several
   obstacles which have prevented site and provider renumbering from
   being feasible in IP version 4.  Arguments about the importance of
   network renumbering for the preservation of a stable routing system
   and for other purposes may be read in [RENUM1, RENUM2, RENUM3].  To
   support the storage of IPv6 addresses without impeding renumbering we
   define the following extensions.





Crawford, et al.            Standards Track