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
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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
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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].
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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 <security> elements.
]
2.1. ical-access:http (update)
<record>
<!-- ical-access:http -->
<class>Application-Based, Common</class>
<type>ical-access</type>
<subtype>http</subtype>
<urischeme>http</urischeme>
<functionalspec>
<paragraph>
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.
</paragraph>
</functionalspec>
<security>
See <xref type="rfc" data="rfcTHIS" />, Section 4.
</security>
<usage>COMMON</usage>
<registrationdocs>
<xref type="rfc" data="rfcTHIS" />
</registrationdocs>
<requesters>
<xref type="person" data="Rohan_Mahy" />
<xref type="person" data="Bernie_Hoeneisen" />
</requesters>
</record>
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2.2. ical-access:https (update)
<record>
<!-- ical-access:https -->
<class>Application-Based, Common</class>
<type>ical-access</type>
<subtype>https</subtype>
<urischeme>https</urischeme>
<functionalspec>
<paragraph>
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.
</paragraph>
</functionalspec>
<security>
See <xref type="rfc" data="rfcTHIS" />, Section 4.
</security>
<usage>COMMON</usage>
<registrationdocs>
<xref type="rfc" data="rfcTHIS" />
</registrationdocs>
<requesters>
<xref type="person" data="Rohan_Mahy" />
<xref type="person" data="Bernie_Hoeneisen" />
</requesters>
</record>
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2.3. ical-sched:mailto (update)
<record>
<!-- ical-sched:mailto -->
<class>Application-Based, Common</class>
<type>ical-sched</type>
<subtype>mailto</subtype>
<urischeme>mailto</urischeme>
<functionalspec>
<paragraph>
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.
</paragraph>
</functionalspec>
<security>
See <xref type="rfc" data="rfcTHIS" />, Section 4.
</security>
<usage>COMMON</usage>
<registrationdocs>
<xref type="rfc" data="rfcTHIS" />
</registrationdocs>
<requesters>
<xref type="person" data="Rohan_Mahy" />
<xref type="person" data="Bernie_Hoeneisen" />
</requesters>
</record>
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2.4. ical-sched:http (new)
TODO: Do we need this one?
<record>
<!-- ical-sched:http -->
<class>Application-Based, Common</class>
<type>ical-sched</type>
<subtype>http</subtype>
<urischeme>http</urischeme>
<functionalspec>
<paragraph>
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.
</paragraph>
</functionalspec>
<security>
See <xref type="rfc" data="rfcTHIS" />, Section 4.
</security>
<usage>COMMON</usage>
<registrationdocs>
<xref type="rfc" data="rfcTHIS" />
</registrationdocs>
<requesters>
<xref type="person" data="Bernie_Hoeneisen"/>
<xref type="person" data="Rohan_Mahy" />
</requesters>
</record>
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2.5. ical-sched:https (new)
<record>
<!-- ical-sched:https -->
<class>Application-Based, Common</class>
<type>ical-sched</type>
<subtype>https</subtype>
<urischeme>https</urischeme>
<functionalspec>
<paragraph>
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.
</paragraph>
</functionalspec>
<security>
See <xref type="rfc" data="rfcTHIS" />, Section 4.
</security>
<usage>COMMON</usage>
<registrationdocs>
<xref type="rfc" data="rfcTHIS" />
</registrationdocs>
<requesters>
<xref type="person" data="Bernie_Hoeneisen" />
<xref type="person" data="Rohan_Mahy" />
</requesters>
</record>
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2.6. Requesters' Addresses
<people>
<person id="Rohan_Mahy">
<name>Rohan Mahy</name>
<org>Unaffiliated</org>
<uri>mailto:rohan&ekabal.com</uri>
<updated>2009-10</updated>
</person>
<person id="Bernie_Hoeneisen">
<name>Bernie Hoeneisen</name>
<org>Ucom Standards Track Solutions GmbH</org>
<uri>mailto:bernhard.hoeneisen@ucom.ch</uri>
<updated>2011-03</updated>
</person>
</people>
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.
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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'
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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,
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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.
[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
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o bernie: several editorials
[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/
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