Network Working Group B. Hoeneisen Internet-Draft Ucom.ch Obsoletes: 5333 (if approved) March 06, 2011 Updates: 6118 (if approved) Intended status: Informational Expires: September 7, 2011 IANA Registration of Enumservices for Internet Calendaring draft-hoeneisen-rfc5333bis-00 Abstract This document registers and updates Enumservices for Internet calendaring. Specifically, this document focuses on Enumservices for scheduling with iMIP (iCalendar Message-Based Interoperability Protocol) and for accessing Internet calendaring information with CalDAV (Calendaring Extensions to WebDAV). Status of this Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. 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." This Internet-Draft will expire on September 7, 2011. Copyright Notice Copyright (c) 2011 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of Hoeneisen Expires September 7, 2011 [Page 1] Internet-Draft Internet Calendaring Enumservices March 2011 the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. This document may contain material from IETF Documents or IETF Contributions published or made publicly available before November 10, 2008. The person(s) controlling the copyright in some of this material may not have granted the IETF Trust the right to allow modifications of such material outside the IETF Standards Process. Without obtaining an adequate license from the person(s) controlling the copyright in such materials, this document may not be modified outside the IETF Standards Process, and derivative works of it may not be created outside the IETF Standards Process, except to format it for publication as an RFC or to translate it into languages other than English. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Enumservice Registrations . . . . . . . . . . . . . . . . . . 4 2.1. ical-access:http (update) . . . . . . . . . . . . . . . . 4 2.2. ical-access:https (update) . . . . . . . . . . . . . . . . 5 2.3. ical-sched:mailto (update) . . . . . . . . . . . . . . . . 6 2.4. ical-sched:http (new) . . . . . . . . . . . . . . . . . . 7 2.5. ical-sched:https (new) . . . . . . . . . . . . . . . . . . 8 2.6. Requesters' Addresses . . . . . . . . . . . . . . . . . . 9 3. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 4. Security Considerations . . . . . . . . . . . . . . . . . . . 9 5. DNS Considerations . . . . . . . . . . . . . . . . . . . . . . 10 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 10 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 11 8.1. Normative References . . . . . . . . . . . . . . . . . . . 11 8.2. Informative References . . . . . . . . . . . . . . . . . . 12 Appendix A. Document Changelog . . . . . . . . . . . . . . . . . 12 Appendix B. Open Issues . . . . . . . . . . . . . . . . . . . . . 13 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 13 Hoeneisen Expires September 7, 2011 [Page 2] Internet-Draft Internet Calendaring Enumservices March 2011 1. Introduction ENUM (E.164 Number Mapping, RFC 6116 [I-D.ietf-enum-3761bis]) is a system that uses DNS (Domain Name System, [RFC1034]) to translate telephone numbers, such as '+12025550100', into URIs (Uniform Resource Identifiers, [RFC3986]), such as 'mailto:user@example.com'. ENUM exists primarily to facilitate the interconnection of systems that rely on telephone numbers with those that use URIs to identify resources. The ENUM registration here could be used to allow phones, for example, to check the free/busy status of a user in their address book or propose a meeting with him or her from the user's phone number. The Guide to Internet Calendaring [RFC3283] describes the relationship between various Internet calendaring specifications like this: "iCalendar [RFC5545] is the language used to describe calendar objects. iTIP [RFC5546] [iCalendar Transport-Independent Interoperability Protocol] describes a way to use the iCalendar language to do scheduling. iMIP [RFC2447] [iCalendar Message-Based Interoperability Protocol] describes how to do iTIP scheduling via e-mail". Recently, another Standards Track protocol for calendar and scheduling access has appeared. CalDAV (Calendaring Extensions to WebDAV) [RFC4791] is a WebDAV (Web-based Distributed Authoring and Versioning) [RFC4918] based mechanism for manipulating Internet calendars, viewing free/busy lists, and via a scheduling extension [I-D.desruisseaux-caldav-sched], could be used for proposing calendar events as well in the future. The existing 'mailto:' URI scheme (defined in [RFC6068]) is already used to address iMIP compatible Calendar Services. Likewise, the existing 'http:' and 'https:' URI schemes (defined in [RFC2616] and [RFC2818]) are already used to address CalDAV compatible Calendar Services. This document updates the existing Calendaring Enumservices specified in [RFC5333] and in Sections 4.7 - 4.9 of RFC 6118 [I-D.ietf-enum-enumservices-transition] to be in line with RFC 6117 [I-D.ietf-enum-enumservices-guide]. Furthermore it adds new Enumservices for WebDAV scheduling [I-D.desruisseaux-caldav-sched]. This document obsoletes [RFC5333] as well as Sections 4.7 - 4.9 of RFC 6118 [I-D.ietf-enum-enumservices-transition]. Hoeneisen Expires September 7, 2011 [Page 3] Internet-Draft Internet Calendaring Enumservices March 2011 2. Enumservice Registrations As defined in RFC 6117 [I-D.ietf-enum-enumservices-guide], the following templates cover the information needed for the registration of the Enumservices specified in this document: [Note for RFC Editor: Please perform this following tasks before publication of this document: o replace any instance of "RFCTHIS" with the RFC number of this document; o replace any instance of "I-D.desruisseaux-caldav-sched" with the RFC number of that document; o verify references pointing to specific sections of this document, in particular in the elements. ] 2.1. ical-access:http (update) Application-Based, Common ical-access http http This Enumservice indicates that the resource identified can be addressed by the associated URI in order to access a user's calendar (for example free/busy status) using the CalDAV [RFC 4791] protocol for Internet calendaring. See , Section 4. COMMON Hoeneisen Expires September 7, 2011 [Page 4] Internet-Draft Internet Calendaring Enumservices March 2011 2.2. ical-access:https (update) Application-Based, Common ical-access https https This Enumservice indicates that the resource identified can be addressed by the associated URI in order to access a user's calendar (for example free/busy status) using the CalDAV [RFC 4791] protocol for Internet calendaring. See , Section 4. COMMON Hoeneisen Expires September 7, 2011 [Page 5] Internet-Draft Internet Calendaring Enumservices March 2011 2.3. ical-sched:mailto (update) Application-Based, Common ical-sched mailto mailto This Enumservice indicates that the resource identified can be addressed by the associated URI used for scheduling using Internet calendaring via Internet mail with the iMIP [RFC 2447] protocol. See , Section 4. COMMON Hoeneisen Expires September 7, 2011 [Page 6] Internet-Draft Internet Calendaring Enumservices March 2011 2.4. ical-sched:http (new) TODO: Do we need this one? Application-Based, Common ical-sched http http This Enumservice indicates that the resource identified can be addressed by the associated URI used for scheduling using Internet calendaring via the scheduling extension [I-D.desruisseaux-caldav-sched] to the CalDAV [RFC 4791] protocol. See , Section 4. COMMON Hoeneisen Expires September 7, 2011 [Page 7] Internet-Draft Internet Calendaring Enumservices March 2011 2.5. ical-sched:https (new) Application-Based, Common ical-sched https https This Enumservice indicates that the resource identified can be addressed by the associated URI used for scheduling using Internet calendaring via the scheduling extension [I-D.desruisseaux-caldav-sched] to the CalDAV [RFC 4791] protocol. See , Section 4. COMMON Hoeneisen Expires September 7, 2011 [Page 8] Internet-Draft Internet Calendaring Enumservices March 2011 2.6. Requesters' Addresses Rohan Mahy Unaffiliated mailto:rohan&ekabal.com 2009-10 Bernie Hoeneisen Ucom Standards Track Solutions GmbH mailto:bernhard.hoeneisen@ucom.ch 2011-03 3. Examples TODO: More Examples $ORIGIN 3.2.1.0.5.5.5.2.1.2.1.e164.arpa. @ NAPTR 10 100 "u" "E2U+ical-access:https" \ "!^.*$!https://cal.example.com/home/alice/calendars/!" . $ORIGIN 3.2.1.0.5.5.5.2.1.2.1.e164.arpa. @ NAPTR 20 100 "u" "E2U+ical-sched:mailto" \ "!^.*$!mailto:alice@example.com!" . 4. Security Considerations The Domain Name System (DNS) does not make policy decisions about which records it provides to a DNS resolver. All DNS records must be assumed to be available to all inquirers at all times. The information provided within an ENUM record set must therefore be considered open to the public -- which is a cause for some privacy considerations. Revealing a calendaring URI by itself is unlikely to introduce many privacy concerns, although, depending on the structure of the URI, it might reveal the full name or employer of the target. The use of anonymous URIs mitigates this risk. Hoeneisen Expires September 7, 2011 [Page 9] Internet-Draft Internet Calendaring Enumservices March 2011 As ENUM uses DNS, which in its current form is an insecure protocol, there is no mechanism for ensuring that the answer returned to a query is authentic. An analysis of threats specific to the dependence of ENUM on the DNS is provided in RFC 6116 [I-D.ietf-enum-3761bis], and a thorough analysis of threats to the DNS itself is covered in [RFC3833]. Many of these problems are prevented when the resolver verifies the authenticity of answers to its ENUM queries via DNSSEC (DNS Security, [RFC4035]) in zones where it is available. More serious security concerns are associated with potential attacks against an underlying calendaring system (for example, unauthorized modification or viewing). For this reason, iTIP discusses a number of security requirements (detailed in [RFC5546]) that call for authentication, integrity and confidentiality properties, and similar measures to prevent such attacks. Any calendaring protocol used in conjunction with a URI scheme currently meets these requirements. The use of CalDAV with the 'https:' scheme makes use of TLS (Transport Layer Security, [RFC5246]) to provide server authentication, confidentiality, and message integrity. Unlike a traditional telephone number, the resource identified by a calendaring URI is often already guessable, and it often requires that users provide cryptographic credentials for authentication and authorization before calendar data can be exchanged. Despite the public availability of ENUM records, the use of this information to reveal an unprotected calendaring resource is unlikely in practice. 5. DNS Considerations These Enumservice registrations add no specific issues related to DNS. 6. IANA Considerations This document requests registration of the "ical-sched" and "ical- access" Enumservices according to the definitions in Section 2 of this document and RFC 6117 [I-D.ietf-enum-enumservices-guide]. 7. Acknowledgments The author would like to thank Alfred Hoenes for providing feedback resulting in improvement of this document. As this document obsoletes [RFC5333], please see also the Authors' Hoeneisen Expires September 7, 2011 [Page 10] Internet-Draft Internet Calendaring Enumservices March 2011 and Acknowledgments sections in RFC 5333 for additional acknowledgments. 8. References 8.1. Normative References [I-D.desruisseaux-caldav-sched] Daboo, C. and B. Desruisseaux, "CalDAV Scheduling Extensions to WebDAV", draft-desruisseaux-caldav-sched-09 (work in progress), October 2010. [I-D.ietf-enum-3761bis] Bradner, S., Conroy, L., and K. Fujiwara, "The E.164 to Uniform Resource Identifiers (URI) Dynamic Delegation Discovery System (DDDS) Application (ENUM)", draft-ietf-enum-3761bis-09 (work in progress), June 2010. [I-D.ietf-enum-enumservices-guide] Hoeneisen, B., Mayrhofer, A., and J. Livingood, "IANA Registration of Enumservices: Guide, Template and IANA Considerations", draft-ietf-enum-enumservices-guide-22 (work in progress), October 2010. [I-D.ietf-enum-enumservices-transition] Hoeneisen, B. and A. Mayrhofer, "Update of legacy IANA Registrations of Enumservices", draft-ietf-enum-enumservices-transition-06 (work in progress), July 2010. [RFC1034] Mockapetris, P., "Domain names - concepts and facilities", STD 13, RFC 1034, November 1987. [RFC2447] Dawson, F., Mansour, S., and S. Silverberg, "iCalendar Message-Based Interoperability Protocol (iMIP)", RFC 2447, November 1998. [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform Resource Identifier (URI): Generic Syntax", STD 66, RFC 3986, January 2005. [RFC4035] Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose, "Protocol Modifications for the DNS Security Extensions", RFC 4035, March 2005. [RFC4791] Daboo, C., Desruisseaux, B., and L. Dusseault, "Calendaring Extensions to WebDAV (CalDAV)", RFC 4791, Hoeneisen Expires September 7, 2011 [Page 11] Internet-Draft Internet Calendaring Enumservices March 2011 March 2007. [RFC4918] Dusseault, L., "HTTP Extensions for Web Distributed Authoring and Versioning (WebDAV)", RFC 4918, June 2007. [RFC5333] Mahy, R. and B. Hoeneisen, "IANA Registration of Enumservices for Internet Calendaring", RFC 5333, October 2009. [RFC5545] Desruisseaux, B., "Internet Calendaring and Scheduling Core Object Specification (iCalendar)", RFC 5545, September 2009. [RFC5546] Daboo, C., "iCalendar Transport-Independent Interoperability Protocol (iTIP)", RFC 5546, December 2009. [RFC6068] Duerst, M., Masinter, L., and J. Zawinski, "The 'mailto' URI Scheme", RFC 6068, October 2010. 8.2. Informative References [RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H., Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999. [RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000. [RFC3283] Mahoney, B., Babics, G., and A. Taler, "Guide to Internet Calendaring", RFC 3283, June 2002. [RFC3833] Atkins, D. and R. Austein, "Threat Analysis of the Domain Name System (DNS)", RFC 3833, August 2004. [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security (TLS) Protocol Version 1.2", RFC 5246, August 2008. Appendix A. Document Changelog [RFC Editor: This section is to be removed before publication] draft-hoeneisen-rfc5333bis-00 (compared to RFC 5333) o bernie: Updated References: 2445 -> 5545, 2446 -> 5546 o bernie: Updated existing Enumservices to be in line with RFC 6117 o bernie: Added new Enumservices for WebDAV scheduling Hoeneisen Expires September 7, 2011 [Page 12] Internet-Draft Internet Calendaring Enumservices March 2011 o bernie: several editorials Appendix B. Open Issues [RFC Editor: This section should be removed before publication] o Major: Do we need "ical-sched:http"? o Minor: References in citation: should those be RFC244[5-6] or RFC554[5-6]? o Minor: Reference to RFC 5689 (Updates RFC 4791) needed? o Minor: Should Rohan be listed as author? o Minor: More examples Author's Address Bernie Hoeneisen Ucom Standards Track Solutions GmbH CH-8000 Zuerich Switzerland Phone: +41 44 500 52 44 Email: bernie@ietf.hoeneisen.ch (bernhard.hoeneisen AT ucom.ch) URI: http://www.ucom.ch/ Hoeneisen Expires September 7, 2011 [Page 13]