RFC 4979

IANA Registration for Enumservice 'XMPP'

📅 published August 2007, from ietf

Okay bestie, let's go! 🎀✨ This is a rewrite of RFC 4979, which is literally the IANA registration for the 'XMPP' Enumservice, so it's the official "hey, XMPP can live in ENUM now" paperwork 💅

Network Working Group, Request for Comments 4979, written by A. Mayrhofer from enum.at, Standards Track, August 2007. It's an Internet standards track protocol doc, and it's basically a registration request (not a brand-new protocol) 🦋 Nothing in this one obsoletes or updates any other RFC. Iconic, right? 👑

Status of This Memo 🌸

This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please check 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, so share the tea 🫶

Copyright Notice 🎀

Abstract ✨

This document asks IANA to register an Enumservice for XMPP, the Extensible Messaging and Presence Protocol 💜 The Enumservice lets people use 'xmpp' Uniform Resource Identifiers (URIs) inside E.164 Number Mapping (ENUM). It's giving "phone number, meet chat address" 📞💖

Table of Contents 🧚

1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 2
2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 2
3.  Enumservice Registration - XMPP . . . . . . . . . . . . . . . . 2
4.  XMPP IRI/URI Considerations for ENUM  . . . . . . . . . . . . . 3
  4.1.  Authority Component . . . . . . . . . . . . . . . . . . . . 3
  4.2.  IRI-to-URI mapping  . . . . . . . . . . . . . . . . . . . . 3
5.  Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
6.  Security and Privacy Considerations . . . . . . . . . . . . . . 4
7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 4
8.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . 4
9.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 5
  9.1.  Normative References  . . . . . . . . . . . . . . . . . . . 5
  9.2.  Informative References  . . . . . . . . . . . . . . . . . . 5

1. Introduction 💖

Okay so ENUM [1] uses the Domain Name System (DNS) [6] to take you from E.164 numbers [7] to Uniform Resource Identifiers (URIs) [3]. Any service you want to use with ENUM MUST be registered with IANA first. Section 3 of RFC 3761 walks you through how that Enumservice registration works 📋

The Extensible Messaging and Presence Protocol (XMPP) [9] lets endpoints stream Extensible Markup Language (XML) [8] elements to each other in close to real time. Mostly it's used for instant messaging, presence, and streaming media, and literally it's so iconic 🌈

RFC 4622 [5] registers a Uniform Resource Identifier (URI) scheme for identifying an XMPP entity, and it can also be an Internationalized Resource Identifier (IRI) [4]. The Enumservice in this document lets you provision those "xmpp" URIs (and the URI forms of "xmpp" IRIs) in ENUM 🦋

2. Terminology 🎀

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [2]. Read those carefully, bestie, they're doing real work 🙈

3. Enumservice Registration - XMPP ✨

Here's the template with the info needed for the IANA registration of the 'XMPP' Enumservice, following Section 3 of RFC 3761:

Enumservice Name: "XMPP"

Enumservice Type: "xmpp"

Enumservice Subtype: n/a

URI Schemes: "xmpp"

Functional Specification:

   This Enumservice indicates that the resource identified is an XMPP
   entity.

Security Considerations: see Section 6
Intended Usage: COMMON

Author: Alexander Mayrhofer <alexander.mayrhofer@enum.at>

4. XMPP IRI/URI Considerations for ENUM 🌸

4.1. Authority Component 🧚

XMPP IRIs/URIs can optionally include an "Authority Component" (see Section 2.3 of RFC 4622). If that component is there, the processing app is signaled to authenticate as the user named in the URI/IRI instead of using the preconfigured identity 🔐

Here's the catch: arbitrary clients can discover and use the XMPP URIs/IRIs tied to an E.164 number. So in most cases those clients won't be able to authenticate as the Authority Component asks, which is a whole vibe-check 💀

So URIs/IRIs that come out of processing an XMPP Enumservice record SHOULD NOT contain an Authority Component. ✋

4.2. IRI-to-URI mapping 🦋

XMPP supports IRIs as well as "plain" URIs, but ENUM itself only supports URIs for Enumservices. Not me being picky, ENUM is just like that 💅

So XMPP IRIs MUST be mapped to URIs for use in an XMPP Enumservice record. The mapping MUST follow the procedures in Section 3.1 of RFC 3987. No skipping this one, periodt 🫶

5. Example 🍓

Here's an example ENUM entry pointing to an XMPP URI:

          $ORIGIN 6.9.4.0.6.9.4.5.1.1.4.4.e164.arpa.
          @  IN NAPTR  ( 100 10 "u"
                         "E2U+xmpp"
                         "!^.*$!xmpp:some-user@example.com!" .
                       )

6. Security and Privacy Considerations 🔐

General security considerations for the protocols this Enumservice registration is built on are covered in Sections 3.1.3 and 6 of RFC 3761 (ENUM), and in Section 14 of RFC 3920 (XMPP). Go read those too, they're the real deal 📚

Okay, real talk, this part is dramatic 😭 ENUM uses DNS, which is a publicly available database. So anything in records provisioned in ENUM domains MUST be considered public too. Even after you revoke the DNS entry and remove the referred resource, copies of that info could still be floating around forever 💀

Information published in ENUM records could reveal links between E.164 numbers and their owners, especially if the IRIs/URIs contain personal identifiers or domain names whose ownership info is easy to look up 🙈

BUT, and this is important, the ENUM record itself doesn't need to contain any personal info. It just points to a place where access to personal info could be granted 🫶

ENUM records pointing to third-party resources can be easily provisioned on purpose by the ENUM domain owner. So any assumption about how a number and an entity are connected could be completely bogus unless some kind of identity verification is in place. That verification is out of scope for this memo, so don't look for it here 😤

7. IANA Considerations 📋

This memo asks IANA to add a new "XMPP" Enumservice to the 'Enumservice Registrations' registry, following the definitions in this document and RFC 3761 [1] 🎀

The required template is in Section 3 ✨

8. Acknowledgements 💜

Some text from RFC 4622 was used in the Introduction of this document. Huge thanks to Charles Clancy, Miguel Garcia, Andrew Newton, Jon Peterson, and Peter Saint-Andre, who gave extensive reviews and valuable feedback 🌟

9. References 🧚

9.1. Normative References 💅

[1] Faltstrom, P. and M. Mealling, "The E.164 to Uniform Resource Identifiers (URI) Dynamic Delegation Discovery System (DDDS) Application (ENUM)", RFC 3761, April 2004.

[2] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997.

[3] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform Resource Identifier (URI): Generic Syntax", STD 66, RFC 3986, January 2005.

[4] Duerst, M. and M. Suignard, "Internationalized Resource Identifiers (IRIs)", RFC 3987, January 2005.

[5] Saint-Andre, P., "Internationalized Resource Identifiers (IRIs) and Uniform Resource Identifiers (URIs) for the Extensible Messaging and Presence Protocol (XMPP)", RFC 4622, July 2006.

9.2. Informative References 🌈

[6] Mockapetris, P., "Domain names - implementation and specification", STD 13, RFC 1035, November 1987.

[7] ITU-T, "The international public telecommunication numbering plan", Recommendation E.164 (02/05), Feb. 2005.

[8] Maler, E., Paoli, J., Bray, T., Yergeau, F., and C. Sperberg- McQueen, "Extensible Markup Language (XML) 1.0 (Third Edition)", World Wide Web Consortium FirstEdition REC-xml-20040204, February 2004, <http://www.w3.org/TR/2004/REC-xml-20040204>.

[9] Saint-Andre, P., Ed., "Extensible Messaging and Presence Protocol (XMPP): Core", RFC 3920, October 2004.

Author's Address 🦋

Alexander Mayrhofer enum.at GmbH Karlsplatz 1/2/9 Wien A-1010 Austria

Phone: +43 1 5056416 34 EMail: alexander.mayrhofer@enum.at URI: http://www.enum.at/

Full Copyright Statement 💜

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This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 🌸

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Acknowledgement 🎀

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📦 where this page comes from

ietf: rfc4979 2007-08
💖 girlified by claude-haiku-5-5 on 2026-10-17: a language model's rewrite of the original, under its terms