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DNS IPv6 Transport Operational Guidelines (RFC3901)

IP.com Disclosure Number: IPCOM000031386D
Original Publication Date: 2004-Sep-01
Included in the Prior Art Database: 2004-Sep-23
Document File: 6 page(s) / 10K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

A. Durand: AUTHOR [+2]

Abstract

This memo provides guidelines and Best Current Practice for operating DNS in a world where queries and responses are carried in a mixed environment of IPv4 and IPv6 networks.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 28% of the total text.

Network Working Group                                          A. Durand

Request for Comments: 3901                        SUN Microsystems, Inc.

BCP: 91                                                         J. Ihren

Category: Best Current Practice                               Autonomica

                                                          September 2004

               DNS IPv6 Transport Operational Guidelines

Status of this Memo

   This document specifies an Internet Best Current Practices for the

   Internet Community, and requests discussion and suggestions for

   improvements.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2004).

Abstract

   This memo provides guidelines and Best Current Practice for operating

   DNS in a world where queries and responses are carried in a mixed

   environment of IPv4 and IPv6 networks.

1.  Introduction to the Problem of Name Space Fragmentation:

    following the referral chain

   A resolver that tries to look up a name starts out at the root, and

   follows referrals until it is referred to a name server that is

   authoritative for the name.  If somewhere down the chain of referrals

   it is referred to a name server that is only accessible over a

   transport which the resolver cannot use, the resolver is unable to

   finish the task.

   When the Internet moves from IPv4 to a mixture of IPv4 and IPv6 it is

   only a matter of time until this starts to happen.  The complete DNS

   hierarchy then starts to fragment into a graph where authoritative

   name servers for certain nodes are only accessible over a certain

   transport.  The concern is that a resolver using only a particular

   version of IP and querying information about another node using the

   same version of IP can not do it because somewhere in the chain of

   servers accessed during the resolution process, one or more of them

   will only be accessible with the other version of IP.

   With all DNS data only available over IPv4 transport everything is

   simple.  IPv4 resolvers can use the intended mechanism of following

   referrals from the root and down while IPv6 resolvers have to work

Durand & Ihren           Best Current Practice                  [Page 1]

RFC 3901             DNS IPv6 Transport Guidelines        September 2004

   through a "translator", i.e., they have to use a recursive name

   server on a so-called "dual stack" host as a "forwarder" since they

   cannot access the DNS data directly.

   With all DNS data only available over IPv6 transport everything would

   be equally simple, with the exception of IPv4 recursive name servers

  ...