Network Working Group J. Klensin
Request for Comments: 3467 February 2003
Category: Informational
Role of the Domain Name System (DNS)
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 (2003). All Rights Reserved.
Abstract
This document reviews the original function and purpose of the domain
name system (DNS). It contrasts that history with some of the
purposes for which the DNS has recently been applied and some of the
newer demands being placed upon it or suggested for it. A framework
for an alternative to placing these additional stresses on the DNS is
then outlined. This document and that framework are not a proposed
solution, only a strong suggestion that the time has come to begin
thinking more broadly about the problems we are encountering and
possible approaches to solving them.
Table of Contents
1. Introduction and History ..................................... 2
1.1 Context for DNS Development ............................... 3
1.2 Review of the DNS and Its Role as Designed ................ 4
1.3 The Web and User-visible Domain Names ..................... 6
1.4 Internet Applications Protocols and Their Evolution ....... 7
2. Signs of DNS Overloading ..................................... 8
3. Searching, Directories, and the DNS .......................... 12
3.1 Overview ................................................. 12
3.2 Some Details and Comments ................................. 14
4. Internationalization ......................................... 15
4.1 ASCII Isn't Just Because of English ....................... 16
4.2 The "ASCII Encoding" Approaches ........................... 17
4.3 "Stringprep" and Its Complexities ......................... 17
4.4 The Unicode Stability Problem ............................. 19
4.5 Audiences, End Users, and the User Interface Problem ...... 20
4.6 Business Cards and Other Natural Uses of Natural Languages. 22
4.7 ASCII Encodings and the Roman Keyboard Assumption ......... 22
Klensin Informational [Page 1]RFC 3467 Role of the Domain Name System (DNS) February 2003
4.8 Intra-DNS Approaches for "Multilingual Names" ............. 23
5. Search-based Systems: The Key Controversies .................. 23
6. Security Considerations ...................................... 24
7. References ................................................... 25
7.1 Normative References ...................................... 25
7.2 Explanatory and Informative References .................... 25
8. Acknowledgements ............................................. 30
9. Author's Address ............................................. 30
10. Full Copyright Statement ..................................... 31
1. Introduction and History
The DNS was designed as a replacement for the older "host table"
system. Both were intended to provide names for network resources at
a more abstract level than network (IP) addresses (see, e.g.,
[RFC625], [RFC811], [RFC819], [RFC830], [RFC882]). In recent years,
the DNS has become a database of convenience for the Internet, with
many proposals to add new features. Only some of these proposals
have been successful. Often the main (or only) motivation for using
the DNS is because it exists and is widely deployed, not because its
existing structure, facilities, and content are appropriate for the
particular application of data involved. This document reviews the
history of the DNS, including examination of some of those newer
applications. It then argues that the overloading process is often
inappropriate. Instead, it suggests that the DNS should be
supplemented by systems better matched to the intended applications
and outlines a framework and rationale for one such system.
Several of the comments that follow are somewhat revisionist. Good
design and engineering often requires a level of intuition by the
designers about things that will be necessary in the future; the
reasons for some of these design decisions are not made explicit at
the time because no one is able to articulate them. The discussion
below reconstructs some of the decisions about the Internet's primary
namespace (the "Class=IN" DNS) in the light of subsequent development
and experience. In addition, the historical reasons for particular
decisions about the Internet were often severely underdocumented
contemporaneously and, not surprisingly, different participants have
different recollections about what happened and what was considered