Message ORGanization Working Group A. Melnikov
Internet-Draft D. Cridland
Intended status: Standards Track Isode Limited
Expires: January 14, 2010 July 13, 2009
IMAP4 Keyword Registry
draft-melnikov-imap-keywords-04
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Abstract
The aim of this document is to establishe a new IANA registry for
IMAP keywords and to define a procedure for keyword registration, in
order to improve interoperability between different IMAP clients.
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Note
A revised version of this draft document will be submitted to the RFC
editor as a Proposed Standard for the Internet Community. Discussion
and suggestions for improvement are requested, and should be sent to
morg@ietf.org.
Table of Contents
1. Conventions used in this document . . . . . . . . . . . . . . 3
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3
3.1. Comments on IMAP Keywords' Registrations . . . . . . . . . . 5
3.2. Change Control . . . . . . . . . . . . . . . . . . . . . . . 5
3.3. Initial registrations . . . . . . . . . . . . . . . . . . . . 5
4. Security Considerations . . . . . . . . . . . . . . . . . . . 7
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
6.1. Normative References . . . . . . . . . . . . . . . . . . . . 7
6.2. Informative References . . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . 8
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1. Conventions used in this document
The 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 RFC 2119 [Kwds].
2. Introduction
IMAP Keywords [RFC3501] are boolean named flags that can be used by
clients to annotate messages in an IMAP mailbox. Although support
for IMAP keywords is an optional feature of IMAP, the majority of
IMAP servers allow for storing of arbitrary keywords. Many
mainstream IMAP clients support some specific keywords, and some can
manage arbitrary IMAP keywords.
Over years some IMAP keywords have become de-facto standard, with
some specific semantics associated with them. In some cases
different client implementors decided to define and use keywords with
different names, but the same semantics. Some server implementors
decided to map such keywords automatically in order to improve cross
client interoperability.
In other cases, the same keywords have been used with different
semantics, thus causing interoperability problems.
This document attempts to prevent further incompatible uses of IMAP
keywords by establishing an IMAP Keyword registry, and documenting a
reserved space for standardized keywords.
3. IANA Considerations
IANA is requested to establish a new registry for IMAP keywords.
Registration of an IMAP keyword is requested by filling in the
following template:
Subject: Registration of IMAP keyword X
IMAP keyword name:
Purpose (description):
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Private or Shared on a server: (One of PRIVATE, SHARED or BOTH.
PRIVATE means that each different user has own copy of
the keyword. SHARED means that all different users see
the same value of the keyword. BOTH means that an IMAP
server can have the keyword as either private or shared.)
Is it an advisory keyword or may it cause an automatic action:
When/by whom the keyword is set/cleared:
Related keywords: (for example "mutually exclusive with keywords Y
and Z")
Related IMAP capabilities:
Security considerations:
Published specification (recommended):
Person & email address to contact for further information:
Intended usage: (One of COMMON, LIMITED USE or OBSOLETE)
Owner/Change controller:
Note: (Any other information that the author deems interesting
may be added here, for example if the keyword(s) is
supported by existing clients.)
and sending it via electronic mail to <iana@iana.org>.
Registration of an IMAP keyword intended for common use requires
Expert Review. This can be performed by posting a review request to
the Message Organization WG mailing list <morg@ietf.org> (or its
replacement as chosen by the responsible Application Area Director).
Keywords intended for widespread use SHOULD start with the "$"
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prefix. IMAP keywords intended for widespread use SHOULD be
standardized in IETF Consensus documents.
Registration of vendor specific keywords is done on First Come First
Serve basis and doesn't require the Expert Review. However such
review is still encouraged. Vendor specific keywords MUST start with
the "vnd." prefix. [[anchor3: SHOULD this be followed by the company
name?]]
3.1. Comments on IMAP Keywords' Registrations
Comments on registered IMAP Keywords should first be sent to the
"owner" of the mechanism and then to the mailing list designated to
IMAP keyword review Section 3
Submitters of comments may, after a reasonable attempt to contact the
owner and after soliciting comments on the IMAP mailing list, request
IANA to attach their comment to the IMAP keyword registration itself
by sending mail to <iana@iana.org>. At IANA sole discretion, IANA
may attach the comment to the IMAP keyword registration.
3.2. Change Control
Once an IMAP keyword registration has been published by IANA, the
author may request a change to its definition. The change request
follows the same procedure as the registration request, with the
exception of changes to the "Person & email address to contact for
further information" and "Owner/Change controller" fields. The
latter can be changed by the owner by sending informing IANA; this
can be done without discussion or review.
The IESG may reassign responsibility for an IMAP keyword. The most
common case of this will be to enable changes to be made to
mechanisms where the author of the registration has died, moved out
of contact or is otherwise unable to make changes that are important
to the community.
IMAP keyword registrations may not be deleted; keywords which are no
longer believed appropriate for use can be declared OBSOLETE by a
change to their "intended usage" field.
The IESG is considered to be the owner of all IMAP keywords which are
on the IETF standards track.
3.3. Initial registrations
IANA is requested to register the following IMAP Keyword in the
registry established in this document:
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Subject: Registration of IMAP keyword $MDNSent
IMAP keyword name: $MDNSent
Purpose (description): Specifies that a Message Disposition
Notification (MDN) must not be sent for any message
annotated with the $MDNSent IMAP keyword.
Private or Shared on a server: SHARED
Is it an advisory keyword or may it cause an automatic action: This
keyword can cause automatic action by the client. See
[RFC3503] for more details
When/by whom the keyword is set/cleared: This keyword is set by an
IMAP client when it decides to act on a MDN request, or
when uploading a sent or draft message.
Related keywords: None
Related IMAP capabilities: None
Security considerations: See section 6 of [RFC3503]
Published specification (recommended): [RFC3503]
Person & email address to contact for further information: Alexey
Melnikov <alexey.melnikov@isode.com>
Intended usage: COMMON
Owner/Change controller: IESG
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Note:
4. Security Considerations
IMAP Keywords are one of the base IMAP features [RFC3501]. This
document doesn't change their behaviour, so it is not adding new
security issues.
A particular IMAP keyword might have specific security
considerations, which are documented in IMAP keyword registration
template standardized by this document.
5. Acknowledgements
The creation of this document was prompted by one of many discussions
on the IMAP mailing list.
John Neystadt co-authored the first revision of this document.
Special thanks to Chris Newman, David Harris, Lyndon Nerenberg and
Mark Crispin for reviewing the document. However all errors or
omissions must be attributed to the author of this document.
The author would also like to thank the developers of Mozilla mail
clients for providing food for thoughts.
6. References
6.1. Normative References
[Kwds] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", RFC 2119, March 1997.
[RFC3501] Crispin, M., "INTERNET MESSAGE ACCESS PROTOCOL - VERSION
4rev1", RFC 3501, March 2003.
6.2. Informative References
[RFC3503] Melnikov, A., "Message Disposition Notification (MDN)
profile for Internet Message Access Protocol (IMAP)",
RFC 3503, March 2003.
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Authors' Addresses
Alexey Melnikov
Isode Limited
5 Castle Business Village
36 Station Road
Hampton, Middlesex TW12 2BX
UK
Email: Alexey.Melnikov@isode.com
URI: http://www.melnikov.ca/
Dave Cridland
Isode Limited
5 Castle Business Village
36 Station Road
Hampton, Middlesex TW12 2BX
UK
Email: dave.cridland@isode.com
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