Network Working Group J. G. Myers Internet Draft: IMAP4 Internationalized Mailboxes Carnegie Mellon Document: internet-drafts/draft-ietf-imap-mbox-00.txt January 1995 IMAP4 Internationalized Mailboxes Status of this memo This document is an Internet Draft. 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. Internet Drafts may be updated, replaced, or obsoleted by other documents at any time. It is not appropriate to use Internet Drafts as reference material or to cite them other than as a ``working draft'' or ``work in progress``. To learn the current status of any Internet-Draft, please check the 1id-abstracts.txt listing contained in the Internet-Drafts Shadow Directories on ds.internic.net, nic.nordu.net, ftp.isi.edu, or munnari.oz.au. This is a draft document of the IETF IMAP Working Group. 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. This document will expire before 15 July 1995. Distribution of this draft is unlimited. Comments are solicited and should be sent to imap@CAC.Washington.EDU. 1. Introduction The Internet Message Access Protocol, Version 4 [RFC1730] contains a number of commands which accept and/or manipulate mailbox names. In the base IMAP4 protocol, mailbox names may only contain characters in the US-ASCII character set. This document defines an extension to the IMAP4 protocol whereby a client and a server may negotiate the use of some other character set for use in mailbox names. Myers [Page 1] Internet Draft IMAP4 Internationalized Mailboxes January 1995 2. MBOXCHARSET capability Servers which support this extension must advertise the MBOXCHARSET capability name in the untagged CAPABILITY response. 3. MBOXCHARSET command Arguments: registered MIME charset name Data: none Result: OK - character set is selected NO - character set is not supported BAD - command unknown or arguments invalid The MBOXCHARSET command selects the character set for use in mailbox names. The command may only be given when a connection is in the authenticated or selected state. If the server does not recognize or support the specified character set name, it must return a tagged NO response. If the server returns a tagged OK response, then all mailbox names (those names corresponding to mailbox or list_mailbox nonterminals in the formal syntax) in subsequent commands and responses are in the specified character set. All servers MUST support the US-ASCII character set. It is not required that any other particular character set be supported. Servers need not support the same set of character sets they support for SEARCH CHARSET. 4. LIST wildcards In the LIST, LSUB, and FIND MAILBOX commands, matching is done on the underlying glyphs, not on the encoded octet stream. The list wildcards are the underlying glyphs which correspond to the US-ASCII characters "*", "%", and in the case of FIND MAILBOX, "?". Requirements imposed on returned mailbox names apply to the underlying glyphs. In character sets where there are multiple possible encodings of the same glyph sequence, the server may pick Myers [Page 2] Internet Draft IMAP4 Internationalized Mailboxes January 1995 whichever encoding is most convenient for it. 5. Examples [Some iso-2022-jp examples] 6. Formal Syntax The following syntax specification uses the augmented Backus-Naur Form (BNF) notation as specified in RFC 822. Except as noted otherwise, all alphabetic characters are case- insensitive. The use of upper or lower case characters to define token strings is for editorial clarity only. Implementations MUST accept these strings in a case-insensitive fashion. mboxcharset ::= "MBOXCHARSET" SP astring ;; Valid only in Authenticated or Selected state ;; Character set must be registered with IANA ;; as a MIME character set 7. References [IMAP4] Crispin, M., "Internet Message Access Protocol - Version 4", RFC 1730, University of Washington, December 1994. 8. Security Considerations Security issues are not discussed in this memo. 9. Author's Address John G. Myers Carnegie-Mellon University 5000 Forbes Ave. Pittsburgh PA, 15213-3890 Email: jgm+@cmu.edu Myers [Page 3]