Network Working Group P. Saint-Andre Internet-Draft XMPP Standards Foundation Intended status: Informational November 7, 2007 Expires: May 10, 2008 The IM-ID Header Field draft-saintandre-header-im-01 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 May 10, 2008. Copyright Notice Copyright (C) The IETF Trust (2007). Abstract This document defines a header field that enables the author of an email or netnews message to include an Instant Messaging (IM) URI in the message header block for the purpose of associating the author with an instant messaging address. Saint-Andre Expires May 10, 2008 [Page 1] Internet-Draft IM-ID November 2007 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Syntax . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Implementation . . . . . . . . . . . . . . . . . . . . . . . . 3 3.1. Inclusion . . . . . . . . . . . . . . . . . . . . . . . . . 3 3.2. Generation . . . . . . . . . . . . . . . . . . . . . . . . 3 3.3. Processing . . . . . . . . . . . . . . . . . . . . . . . . 4 3.4. Disposition . . . . . . . . . . . . . . . . . . . . . . . . 4 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 May 10, 2008 [Page 2] Internet-Draft IM-ID November 2007 1. Introduction Several technologies enable entities to exchange messages in close to real time, also known as "instant messaging" or IM [IMP-REQS]. Such technologies include the Extensible Messaging and Presence Protocol [XMPP-IM] and the Session Initiation Protocol [SIP-IM]. To facilitate the exchange of instant messages, a URI scheme for IM is defined in [CPIM]. Because almost all human users of instant messaging systems also use email systems and because many such users also use netnews systems, it can be helpful for such users to specify their IM URIs in the messages they author. The IM-ID header field provides a standard location for such information. This document documents the syntax and implementation of the IM-ID header field, including the information necessary to register it in the Permanent Message Header Field Registry maintained by the IANA. 2. Syntax The syntax of the IM-ID header field is defined below using Augmented Backus-Naur Form (as specified by [ABNF]), where the "IM-URI" rule is defined in [CPIM] and the remaining rules are defined in [MESSAGE]: "IM-ID:" SP *WSP pathxmpp *WSP CRLF 3. Implementation 3.1. Inclusion The IM-ID header field is associated with the author of the message; see [MESSAGE]. If the "From:" header field contains more than one mailbox, the IM-ID header field should not be added to the message. There should be no more than one instance of the IM-ID header field. 3.2. Generation For a user whose instant messaging URI is "im:juliet@example.com", the corresponding IM-ID header field would be: IM-ID: im:juliet@example.com Saint-Andre Expires May 10, 2008 [Page 3] Internet-Draft IM-ID November 2007 3.3. Processing Upon receiving a message containing an IM-ID header field, a user agent that supports the field should process the field by resolving the instant messaging URI in accordance with the procedures specified in [CPIM]. 3.4. Disposition A user agent that has processed an IM-ID header field may provide appropriate interface elements if it has independent information linking the author of the message with the specified instant messaging URI (e.g., via a user-controlled address book or automated directory lookup). Such interface elements might include an element that enables the user to initiate a text chat with the author. 4. IANA Considerations In accordance with [REG], the IANA registers the "IM-ID" header field in the Permanent Message Header Field Registry. The registration template is as follows: Header field name: IM-ID Applicable protocol: mail, netnews Status: permanent Author/Change controller: Peter Saint-Andre Specification document(s): draft-saintandre-header-im-00 [Note to IANA and RFC Editor: Replace I-D name with RFC XXXX, where "XXXX" is the number of the RFC that results from this specification, if any] Related information: For detail information regarding instant messaging URIs, refer to RFC 3860. 5. Security Considerations Message headers are an existing standard and are designed to easily accommodate new types. Although the IM-ID header field may be forged, this problem is inherent in Internet email; however, because a forged IM-ID header field may break automated processing, applications should not depend on the IM-ID header field to indicate the authenticity of an email message or the identity of its author or sender. Including the IM-ID header field among the signer header fields in DomainKeys Identified Mail (DKIM) can help to mitigate against forging of the header (see [DKIMSIG]). Saint-Andre Expires May 10, 2008 [Page 4] Internet-Draft IM-ID November 2007 Advertising instant messaging URIs in message headers may make it easier for malicious users to harvest such URIs and therefore to send unsolicited bulk communications to the users or applications represented by those URIs. Care should be taken in balancing the benefits of open information exchange against the potential costs of unwanted communication. An user agent that is capable of including the IM-ID header field in outgoing messages should provide an option for its user to disable inclusion of the IM-ID header field generally, on a per-recipient basis, and on a per-message basis. The security considerations discussed in [URI] and [CPIM] may also apply to the IM-ID message header. 6. References 6.1. Normative References [ABNF] Crocker, D. and P. Overell, "Augmented BNF for Syntax Specifications: ABNF", RFC 4234, October 2005. [CPIM] Peterson, J., "Common Profile for Instant Messaging (CPIM)", RFC 3860, August 2004. [MESSAGE] Resnick, P., "Internet Message Format", RFC 2822, April 2001. 6.2. Informative References [DKIMSIG] Allman, E., Callas, J., Delany, M., Libbey, M., Fenton, J., and M. Thomas, "DomainKeys Identified Mail (DKIM) Signatures", RFC 4871, May 2007. [IMP-REQS] Day, M., Aggarwal, S., and J. Vincent, "Instant Messaging / Presence Protocol Requirements", RFC 2779, February 2000. [REG] Klyne, G., Nottingham, M., and J. Mogul, "Registration Procedures for Message Header Fields", BCP 90, RFC 3864, September 2004. [SIP-IM] Campbell, B., Rosenberg, J., Schulzrinne, H., Huitema, C., and D. Gurle, "Session Initiation Protocol (SIP) Extension for Instant Messaging", RFC 3428, December 2002. [URI] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform Resource Identifier (URI): Generic Syntax", STD 66, Saint-Andre Expires May 10, 2008 [Page 5] Internet-Draft IM-ID November 2007 RFC 3986, January 2005. [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: https://stpeter.im/ Saint-Andre Expires May 10, 2008 [Page 6] Internet-Draft IM-ID November 2007 Full Copyright Statement Copyright (C) The IETF Trust (2007). 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