IPv6 Host Configuration of DNS Server Information Approaches
RFC 4339

Network Working Group                                      J. Jeong, Ed.
Request for Comments: 4339                  ETRI/University of Minnesota
Category: Informational                                    February 2006

      IPv6 Host Configuration of DNS Server Information Approaches

Status of This Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard of any kind.  Distribution of this
   memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2006).

IESG Note

   This document describes three different approaches for the
   configuration of DNS name resolution server information in IPv6
   hosts.

   There is not an IETF consensus on which approach is preferred.  The
   analysis in this document was developed by the proponents for each
   approach and does not represent an IETF consensus.

   The 'RA option' and 'Well-known anycast' approaches described in this
   document are not standardized.  Consequently the analysis for these
   approaches might not be completely applicable to any specific
   proposal that might be proposed in the future.

Abstract

   This document describes three approaches for IPv6 recursive DNS
   server address configuration.  It details the operational attributes
   of three solutions: RA option, DHCPv6 option, and well-known anycast
   addresses for recursive DNS servers.  Additionally, it suggests the
   deployment scenarios in four kinds of networks (ISP, enterprise,
   3GPP, and unmanaged networks) considering multi-solution resolution.

Jeong                        Informational                      [Page 1]
RFC 4339         IPv6 Host Configuration of DNS Server     February 2006

Table of Contents

   1. Introduction ....................................................3
   2. Terminology .....................................................3
   3. IPv6 DNS Configuration Approaches ...............................3
      3.1. RA Option ..................................................3
           3.1.1. Advantages ..........................................4
           3.1.2. Disadvantages .......................................5
           3.1.3. Observations ........................................5
      3.2. DHCPv6 Option ..............................................6
           3.2.1. Advantages ..........................................7
           3.2.2. Disadvantages .......................................8
           3.2.3. Observations ........................................9
      3.3. Well-known Anycast Addresses ...............................9
           3.3.1. Advantages .........................................10
           3.3.2. Disadvantages ......................................10
           3.3.3. Observations .......................................10
   4. Interworking among IPv6 DNS Configuration Approaches ...........11
   5. Deployment Scenarios ...........................................12
      5.1. ISP Network ...............................................12
           5.1.1. RA Option Approach .................................13
           5.1.2. DHCPv6 Option Approach .............................13
           5.1.3. Well-known Anycast Addresses Approach ..............14
      5.2. Enterprise Network ........................................14
      5.3. 3GPP Network ..............................................15
           5.3.1. Currently Available Mechanisms and
                  Recommendations ....................................15
           5.3.2. RA Extension .......................................16
           5.3.3. Stateless DHCPv6 ...................................16
           5.3.4. Well-known Addresses ...............................17
           5.3.5. Recommendations ....................................18
      5.4. Unmanaged Network .........................................18
           5.4.1. Case A: Gateway Does Not Provide IPv6 at All .......18
           5.4.2. Case B: A Dual-stack Gateway Connected to a
                  Dual-stack ISP .....................................19
           5.4.3. Case C: A Dual-stack Gateway Connected to
                  an IPv4-only ISP ...................................19
           5.4.4. Case D: A Gateway Connected to an IPv6-only ISP ....19
   6. Security Considerations ........................................19
      6.1. RA Option .................................................20
      6.2. DHCPv6 Option .............................................21
      6.3. Well-known Anycast Addresses ..............................21
   7. Contributors ...................................................21
   8. Acknowledgements ...............................................23
   9. References .....................................................23