IMAP Support for UTF-8
RFC 6855
| Document | Type |
RFC - Proposed Standard
(March 2013; Errata)
Obsoletes RFC 5738
Was draft-ietf-eai-5738bis (eai WG)
|
|
|---|---|---|---|
| Last updated | 2020-01-21 | ||
| Replaces | draft-ietf-eai-5378bis | ||
| Stream | IETF | ||
| Formats | plain text html pdf htmlized with errata bibtex | ||
| Reviews | |||
| Stream | WG state | WG Document | |
| Document shepherd | John Klensin | ||
| Shepherd write-up | Show (last changed 2012-08-24) | ||
| IESG | IESG state | RFC 6855 (Proposed Standard) | |
| Consensus Boilerplate | Unknown | ||
| Telechat date | |||
| Responsible AD | Barry Leiba | ||
| Send notices to | (None) | ||
Internet Engineering Task Force (IETF) P. Resnick, Ed.
Request for Comments: 6855 Qualcomm Incorporated
Obsoletes: 5738 C. Newman, Ed.
Category: Standards Track Oracle
ISSN: 2070-1721 S. Shen, Ed.
CNNIC
March 2013
IMAP Support for UTF-8
Abstract
This specification extends the Internet Message Access Protocol
(IMAP) to support UTF-8 encoded international characters in user
names, mail addresses, and message headers. This specification
replaces RFC 5738.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc6855.
Copyright Notice
Copyright (c) 2013 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
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Resnick, et al. Standards Track [Page 1]
RFC 6855 IMAP Support for UTF-8 March 2013
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions Used in This Document . . . . . . . . . . . . . . 2
3. "UTF8=ACCEPT" IMAP Capability and UTF-8 in IMAP
Quoted-Strings . . . . . . . . . . . . . . . . . . . . . . . . 3
4. IMAP UTF8 "APPEND" Data Extension . . . . . . . . . . . . . . 4
5. "LOGIN" Command and UTF-8 . . . . . . . . . . . . . . . . . . 5
6. "UTF8=ONLY" Capability . . . . . . . . . . . . . . . . . . . . 5
7. Dealing with Legacy Clients . . . . . . . . . . . . . . . . . 6
8. Issues with UTF-8 Header Mailstore . . . . . . . . . . . . . . 7
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
10. Security Considerations . . . . . . . . . . . . . . . . . . . 8
11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 9
11.1. Normative References . . . . . . . . . . . . . . . . . . 9
11.2. Informative References . . . . . . . . . . . . . . . . . 10
Appendix A. Design Rationale . . . . . . . . . . . . . . . . . . 11
Appendix B. Acknowledgments . . . . . . . . . . . . . . . . . . . 11
1. Introduction
This specification forms part of the Email Address
Internationalization protocols described in the Email Address
Internationalization Framework document [RFC6530]. It extends IMAP
[RFC3501] to permit UTF-8 [RFC3629] in headers, as described in
"Internationalized Email Headers" [RFC6532]. It also adds a
mechanism to support mailbox names using the UTF-8 charset. This
specification creates two new IMAP capabilities to allow servers to
advertise these new extensions.
This specification assumes that the IMAP server will be operating in
a fully internationalized environment, i.e., one in which all clients
accessing the server will be able to accept non-ASCII message header
fields and other information, as specified in Section 3. At least
during a transition period, that assumption will not be realistic for
many environments; the issues involved are discussed in Section 7
below.
This specification replaces an earlier, experimental approach to the
same problem [RFC5738].
2. Conventions Used in This Document
The key words "MUST", "MUST NOT", "SHOULD", "SHOULD NOT", and "MAY"
in this document are to be interpreted as defined in "Key words for
use in RFCs to Indicate Requirement Levels" [RFC2119].
Resnick, et al. Standards Track [Page 2]
RFC 6855 IMAP Support for UTF-8 March 2013
The formal syntax uses the Augmented Backus-Naur Form (ABNF)
[RFC5234] notation. In addition, rules from IMAP [RFC3501], UTF-8
[RFC3629], Extensions to IMAP ABNF [RFC4466], and IMAP "LIST" command
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