Architectural Considerations on Application Features in the DNS
RFC 6950
Internet Architecture Board (IAB) J. Peterson
Request for Comments: 6950 NeuStar, Inc.
Category: Informational O. Kolkman
ISSN: 2070-1721 NLnet Labs
H. Tschofenig
Nokia Siemens Networks
B. Aboba
Skype
October 2013
Architectural Considerations on Application Features in the DNS
Abstract
A number of Internet applications rely on the Domain Name System
(DNS) to support their operations. Many applications use the DNS to
locate services for a domain; some, for example, transform
identifiers other than domain names into formats that the DNS can
process, and then fetch application data or service location data
from the DNS. Proposals incorporating sophisticated application
behavior using DNS as a substrate have raised questions about the
role of the DNS as an application platform. This document explores
the architectural consequences of using the DNS to implement certain
application features, and it provides guidance to future application
designers as to the limitations of the DNS as a substrate and the
situations in which alternative designs should be considered.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for informational purposes.
This document is a product of the Internet Architecture Board (IAB)
and represents information that the IAB has deemed valuable to
provide for permanent record. It represents the consensus of the
Internet Architecture Board (IAB). Documents approved for
publication by the IAB are not a candidate for any level of Internet
Standard; see 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/rfc6950.
Peterson, et al. Informational [Page 1]
RFC 6950 Application Features in DNS October 2013
Copyright Notice
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document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
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Table of Contents
1. Motivation ......................................................2
2. Overview of DNS Application Usages ..............................4
2.1. Locating Services in a Domain ..............................5
2.2. NAPTR and DDDS .............................................6
2.3. Arbitrary Data in the DNS ..................................8
3. Challenges for the DNS .........................................10
3.1. Compound Queries ..........................................10
3.1.1. Responses Tailored to the Originator ...............12
3.2. Using DNS as a Generic Database ...........................14
3.2.1. Large Data in the DNS ..............................14
3.3. Administrative Structures Misaligned with the DNS .........16
3.3.1. Metadata about Tree Structure ......................18
3.4. Domain Redirection ........................................20
4. Private DNS and Split Horizon ..................................21
5. Principles and Guidance ........................................23
6. Security Considerations ........................................25
7. IAB Members at the Time of Approval ............................26
8. Acknowledgements ...............................................26
9. Informative References .........................................27
1. Motivation
The Domain Name System (DNS) has long provided a general means of
translating domain names into Internet Protocol addresses, which
makes the Internet easier to use by providing a valuable layer of
indirection between names and lower-layer protocol elements.
[RFC0974] documented a further use of the DNS: to locate an
application service operating in a domain, via the Mail Exchange (MX)
Resource Record; these records help email addressed to the domain to
find a mail service for the domain sanctioned by the zone
administrator.
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RFC 6950 Application Features in DNS October 2013
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