The Naming Authority Pointer (NAPTR) DNS Resource Record
RFC 2915
Document | Type |
RFC - Proposed Standard
(September 2000; No errata)
Updates RFC 2168
|
|
---|---|---|---|
Authors | Michael Mealling , Ron Daniel | ||
Last updated | 2013-03-02 | ||
Stream | Internent Engineering Task Force (IETF) | ||
Formats | plain text html pdf htmlized (tools) htmlized bibtex | ||
Stream | WG state | (None) | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 2915 (Proposed Standard) | |
Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | (None) | ||
Send notices to | (None) |
Network Working Group M. Mealling Request for Comments: 2915 Network Solutions, Inc. Updates: 2168 R. Daniel Category: Standards Track DATAFUSION, Inc. September 2000 The Naming Authority Pointer (NAPTR) DNS Resource Record Status of this Memo This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited. Copyright Notice Copyright (C) The Internet Society (2000). All Rights Reserved. Abstract This document describes a Domain Name System (DNS) resource record which specifies a regular expression based rewrite rule that, when applied to an existing string, will produce a new domain label or Uniform Resource Identifier (URI). Depending on the value of the flags field of the resource record, the resulting domain label or URI may be used in subsequent queries for the Naming Authority Pointer (NAPTR) resource records (to delegate the name lookup) or as the output of the entire process for which this system is used (a resolution server for URI resolution, a service URI for ENUM style e.164 number to URI mapping, etc). This allows the DNS to be used to lookup services for a wide variety of resource names (including URIs) which are not in domain name syntax. Reasons for doing this range from URN Resource Discovery Systems to moving out-of-date services to new domains. This document updates the portions of RFC 2168 specifically dealing with the definition of the NAPTR records and how other, non-URI specific applications, might use NAPTR. Mealling & Daniel Standards Track [Page 1] RFC 2915 NAPTR DNS RR September 2000 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. NAPTR RR Format . . . . . . . . . . . . . . . . . . . . . . 3 3. Substitution Expression Grammar . . . . . . . . . . . . . . 7 4. The Basic NAPTR Algorithm . . . . . . . . . . . . . . . . . 8 5. Concerning How NAPTR Uses SRV Records . . . . . . . . . . . 9 6. Application Specifications . . . . . . . . . . . . . . . . . 10 7. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 10 7.1 Example 1 . . . . . . . . . . . . . . . . . . . . . . . . . 10 7.2 Example 2 . . . . . . . . . . . . . . . . . . . . . . . . . 12 7.3 Example 3 . . . . . . . . . . . . . . . . . . . . . . . . . 13 8. DNS Packet Format . . . . . . . . . . . . . . . . . . . . . 13 9. Master File Format . . . . . . . . . . . . . . . . . . . . . 14 10. Advice for DNS Administrators . . . . . . . . . . . . . . . 14 11. Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 12. IANA Considerations . . . . . . . . . . . . . . . . . . . . 15 13. Security Considerations . . . . . . . . . . . . . . . . . . 15 14. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . 16 References . . . . . . . . . . . . . . . . . . . . . . . . . 16 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . 17 Full Copyright Statement . . . . . . . . . . . . . . . . . . 18 1. Introduction This RR was originally produced by the URN Working Group [3] as a way to encode rule-sets in DNS so that the delegated sections of a URI could be decomposed in such a way that they could be changed and re- delegated over time. The result was a Resource Record that included a regular expression that would be used by a client program to rewrite a string into a domain name. Regular expressions were chosen for their compactness to expressivity ratio allowing for a great deal of information to be encoded in a rather small DNS packet. The function of rewriting a string according to the rules in a record has usefulness in several different applications. This document defines the basic assumptions to which all of those applications must adhere to. It does not define the reasons the rewrite is used, what the expected outcomes are, or what they are used for. Those are specified by applications that define how they use the NAPTR record and algorithms within their contexts. Flags and other fields are also specified in the RR to control the rewrite procedure in various ways or to provide information on how to communicate with the host at the domain name that was the result of the rewrite. Mealling & Daniel Standards Track [Page 2]Show full document text