Network Working Group P. Saint-Andre Internet-Draft XSF Expires: October 11, 2007 April 9, 2007 The Jabber-ID Header Field draft-saintandre-jabberid-05 Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on October 11, 2007. Copyright Notice Copyright (C) The IETF Trust (2007). Abstract This document defines a header field that enables a sender to include a Jabber Identifier in the header block of an email message for the purpose of associating the email message or sender with a particular Extensible Messaging and Presence Protocol (XMPP) address. Saint-Andre Expires October 11, 2007 [Page 1] Internet-Draft Jabber-ID April 2007 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Jabber-ID Syntax . . . . . . . . . . . . . . . . . . . . . . . 3 3. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 4 5. Security Considerations . . . . . . . . . . . . . . . . . . . . 4 6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 5 6.1. Normative References . . . . . . . . . . . . . . . . . . . 5 6.2. Informative References . . . . . . . . . . . . . . . . . . 5 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 6 Intellectual Property and Copyright Statements . . . . . . . . . . 7 Saint-Andre Expires October 11, 2007 [Page 2] Internet-Draft Jabber-ID April 2007 1. Introduction The Extensible Messaging and Presence Protocol (XMPP), documented in [XMPP-CORE], is a streaming XML technology that enables any two entities on a network to exchange well-defined but extensible XML elements (called "XML stanzas") in close to real time. Given XMPP's heritage in the Jabber open-source community, one of the primary uses for XMPP is instant messaging and presence as documented in [XMPP-IM], and XMPP addresses are still referred to as Jabber Identifiers or Jabber IDs. Because almost all users of Jabber/XMPP instant messaging and presence systems are users of email systems, it can be helpful for such users to specify their Jabber Identifiers in the email messages they send. The Jabber-ID header defined in this document provides a standard location for that information. 2. Jabber-ID Syntax The syntax of the Jabber-ID header is defined below using Augmented Backus-Naur Form (as specified by [ABNF]), where the "pathxmpp" rule is defined in [XMPP-URI] and the remaining rules are defined in [MESSAGE]: "Jabber-ID:" [FWS] pathxmpp (*WSP / obs-FWS) CRLF Note: Although a native XMPP address may contain virtually any [UNICODE] character, an electronic mail header may contain only printable [US-ASCII] characters (see Section 2 of [MESSAGE]). Therefore, any non-US-ASCII characters in an XMPP address must be converted to US-ASCII before inclusion in a Jabber-ID header, in accordance with the rules specified in [XMPP-URI]. In addition, characters allowed in XMPP node identifiers and XMPP resource identifiers but disallowed by the relevant URI rules must be percent- encoded in accordance with the rules specified in [URI]; for details, see [XMPP-URI]. 3. Examples For a user whose XMPP address is "juliet@example.com", the corresponding Jabber-ID header would be: Jabber-ID: juliet@example.com As noted, non-US-ASCII characters in XMPP addresses must be converted into US-ASCII before inclusion in a Jabber-ID header. Consider the Saint-Andre Expires October 11, 2007 [Page 3] Internet-Draft Jabber-ID April 2007 following XMPP address: jiři@čechy.example Note: The string "ř" stands for the Unicode character LATIN SMALL LETTER R WITH CARON and the string "č" stands for the Unicode character LATIN SMALL LETTER C WITH CARON, following the "XML Notation" used in [IRI] to represent characters that cannot be rendered in ASCII-only documents (note also that these characters are represented in their stringprep canonical form; see [STRINGPREP]). For those who do not read Czech, this example could be Anglicized as "george@czech-lands.example". Following the rules in [XMPP-URI] and the Jabber-ID header syntax, the resulting header would be: Jabber-ID: ji%C5%99i@%C4%8Dechy.example 4. IANA Considerations In accordance with [REG], the IANA registers the "Jabber-ID" header field in the Permanent Message Header Field Registry. The registration template is as follows: Header field name: Jabber-ID Applicable protocol: mail Status: standard Author/Change controller: IETF Specification document(s): XXXX Related information: For details regarding the native usage and format of Jabber Identifiers, see Extensible Messaging and Presence Protocol (RFC 3920). 5. Security Considerations Message headers are an existing standard and are designed to easily accommodate new types. Although the Jabber-ID header may be forged, this problem is inherent in Internet email; however, because a forged Jabber-ID header may break automated processing, applications should not depend on the Jabber-ID header to indicate the authenticity of an email message or the identity of its sender. Advertising XMPP addresses in email headers may make it easier for malicious users to harvest XMPP addresses and therefore to send unsolicited bulk communications to the users or applications represented by those addresses. Care should be taken in balancing Saint-Andre Expires October 11, 2007 [Page 4] Internet-Draft Jabber-ID April 2007 the benefits of open information exchange against the potential costs of unwanted communications. An email user agent that is capable of including the Jabber-ID header field in outgoing email messages should provide an option for its user to disable inclusion of the Jabber-ID header field generally, on a per-recipient basis, or on a per-message basis. 6. References 6.1. Normative References [ABNF] Crocker, D. and P. Overell, "Augmented BNF for Syntax Specifications: ABNF", RFC 4234, October 2005. [MESSAGE] Resnick, P., "Internet Message Format", RFC 2822, April 2001. [XMPP-URI] Saint-Andre, P., "Internationalized Resource Identifiers (IRIs) and Uniform Resource Identifiers (URIs) for the Extensible Messaging and Presence Protocol (XMPP)", draft-saintandre-rfc4622bis-00 (work in progress), April 2007. 6.2. Informative References [IRI] Duerst, M. and M. Suignard, "Internationalized Resource Identifiers (IRIs)", RFC 3987, January 2005. [REG] Klyne, G., Nottingham, M., and J. Mogul, "Registration Procedures for Message Header Fields", BCP 90, RFC 3864, September 2004. [STRINGPREP] Hoffman, P. and M. Blanchet, "Preparation of Internationalized Strings ("stringprep")", RFC 3454, December 2002. [UNICODE] The Unicode Consortium, "The Unicode Standard, Version 3.2.0", 2000. The Unicode Standard, Version 3.2.0 is defined by The Unicode Standard, Version 3.0 (Reading, MA, Addison- Wesley, 2000. ISBN 0-201-61633-5), as amended by the Unicode Standard Annex #27: Unicode 3.1 (http://www.unicode.org/reports/tr27/) and by the Unicode Standard Annex #28: Unicode 3.2 Saint-Andre Expires October 11, 2007 [Page 5] Internet-Draft Jabber-ID April 2007 (http://www.unicode.org/reports/tr28/). [URI] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform Resource Identifier (URI): Generic Syntax", STD 66, RFC 3986, January 2005. [US-ASCII] American National Standards Institute, "Coded Character Set - 7-bit American Standard Code for Information Interchange", ANSI X3.4, 1986. [XMPP-CORE] Saint-Andre, P., "Extensible Messaging and Presence Protocol (XMPP): Core", RFC 3920, October 2004. [XMPP-IM] Saint-Andre, P., "Extensible Messaging and Presence Protocol (XMPP): Instant Messaging and Presence", RFC 3921, October 2004. Author's Address Peter Saint-Andre XMPP Standards Foundation Email: stpeter@jabber.org URI: xmpp:stpeter@jabber.org Saint-Andre Expires October 11, 2007 [Page 6] Internet-Draft Jabber-ID April 2007 Full Copyright Statement Copyright (C) The IETF Trust (2007). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. 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Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org. Acknowledgment Funding for the RFC Editor function is provided by the IETF Administrative Support Activity (IASA). Saint-Andre Expires October 11, 2007 [Page 7]