Network Working Group P. Saint-Andre Internet-Draft JSF Expires: August 20, 2006 February 16, 2006 The Jabber-ID Email Header draft-saintandre-jabberid-00 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 August 20, 2006. Copyright Notice Copyright (C) The Internet Society (2006). Abstract This document defines an electronic mail header 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 address on an Extensible Messaging and Presence Protocol (XMPP) network. Saint-Andre Expires August 20, 2006 [Page 1] Internet-Draft Jabber-ID February 2006 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Jabber-ID Syntax . . . . . . . . . . . . . . . . . . . . . . . 3 3. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 4. Security Considerations . . . . . . . . . . . . . . . . . . . 4 5. Normative References . . . . . . . . . . . . . . . . . . . . . 4 Author's Address . . . . . . . . . . . . . . . . . . . . . . . 5 Intellectual Property and Copyright Statements . . . . . . . . 6 Saint-Andre Expires August 20, 2006 [Page 2] Internet-Draft Jabber-ID February 2006 1. Introduction The Extensible Messaging and Presence Protocol (XMPP), documented in [RFC3920], 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 [RFC3921], and XMPP addresses are still referred to as Jabber Identifiers. Because almost all users of Jabber instant messaging and presence systems are users of email systems, it would 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. The capitalized 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 [RFC2119]. 2. Jabber-ID Syntax The syntax of the Jabber-ID header is defined below using Augmented Backus-Naur Form (as specified by [RFC4234]), where the "pathxmpp" rule is defined in [XMPP-URI] and CRLF is defined in [RFC2822]: "Jabber-ID: " pathxmpp CRLF 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 [RFC2822]). 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]. 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 following XMPP address: Saint-Andre Expires August 20, 2006 [Page 3] Internet-Draft Jabber-ID February 2006 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 [RFC3987] to represent characters that cannot be rendered in ASCII-only documents (note also that these characters are represented in their stringprep canonical form). 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. 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. A forged Jabber-ID header may break automated processing; therefore the Jabber-ID header SHOULD NOT be depended upon to indicate the authenticity of the message or the identity of the 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 the benefits of open information exchange against the potential costs of unwanted communications. 5. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC2822] Resnick, P., "Internet Message Format", RFC 2822, April 2001. [RFC3920] Saint-Andre, P., "Extensible Messaging and Presence Protocol (XMPP): Core", RFC 3920, October 2004. [RFC3921] Saint-Andre, P., "Extensible Messaging and Presence Protocol (XMPP): Instant Messaging and Presence", RFC 3921, October 2004. Saint-Andre Expires August 20, 2006 [Page 4] Internet-Draft Jabber-ID February 2006 [RFC3987] Duerst, M. and M. Suignard, "Internationalized Resource Identifiers (IRIs)", RFC 3987, January 2005. [RFC4234] Crocker, D. and P. Overell, "Augmented BNF for Syntax Specifications: ABNF", RFC 4234, October 2005. [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 (http://www.unicode.org/reports/tr28/). [US-ASCII] American National Standards Institute, "Coded Character Set - 7-bit American Standard Code for Information Interchange", ANSI X3.4, 1986. [XMPP-URI] Saint-Andre, P., "Internationalized Resource Identifiers (IRIs) and Uniform Resource Identifiers (URIs) for the Extensible Messaging and Presence Protocol (XMPP)", draft-saintandre-xmpp-iri-03 (work in progress), December 2005. Author's Address Peter Saint-Andre Jabber Software Foundation Email: stpeter@jabber.org URI: xmpp:stpeter@jabber.org Saint-Andre Expires August 20, 2006 [Page 5] Internet-Draft Jabber-ID February 2006 Intellectual Property Statement The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. 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Disclaimer of Validity 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 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. Copyright Statement Copyright (C) The Internet Society (2006). 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. Acknowledgment Funding for the RFC Editor function is currently provided by the Internet Society. Saint-Andre Expires August 20, 2006 [Page 6]