Network Working Group J. G. Myers Internet Draft: IMAP4 Internationalized Mailboxes Carnegie Mellon Document: internet-drafts/draft-ietf-imap-mbox-01.txt September 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: 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. The previously selected character set remains. 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 octets of the encoded stream. The list wildcards are the underlying glyphs which correspond to the US-ASCII glyphs "*", "%", 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 Myers [Page 2] Internet Draft IMAP4 Internationalized Mailboxes January 1995 possible encodings of the same glyph sequence, the server may pick whichever encoding is most convenient for it. 5. Example In the following example, the sequence ``^['' represents ESC, an octet with decimal value 27. C: A003 MBOXCHARSET iso-2022-jp S: A003 OK Mailbox names using iso-2022-jp charset C: A004 LIST "" "^[$B$*5R$5$s$,5%^[(J*" S: * LIST () "/" "$B$*5R$5$s$,5%