draft-ietf-imapext-i18n-03.txt   draft-ietf-imapext-i18n-04.txt 
Network Working Group Chris Newman Network Working Group Chris Newman
Request for Comments: DRAFT Sun Microsystems Request for Comments: DRAFT Sun Microsystems
draft-ietf-imapext-i18n-03.txt Arnt Gulbrandsen draft-ietf-imapext-i18n-04.txt Arnt Gulbrandsen
Oryx Mail Systems Oryx Mail Systems
June 2004 October 2004
Internet Message Access Protocol Internationalization Internet Message Access Protocol Internationalization
Status of this Memo Status of this Memo
By submitting this Internet-Draft, I certify that any applicable
patent or other IPR claims of which I am aware have been disclosed,
and any of which I become aware will be disclosed, in accordance
with RFC 3668.
This document is an Internet-Draft and is in full conformance with This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026. Internet-Drafts are all provisions of Section 10 of RFC2026. Internet-Drafts are
working documents of the Internet Engineering Task Force (IETF), its working documents of the Internet Engineering Task Force (IETF), its
areas, and its working groups. Note that other groups may also areas, and its working groups. Note that other groups may also
distribute working documents as Internet-Drafts. distribute working documents as Internet-Drafts.
Internet-Drafts are draft documents valid for a maximum of six Internet-Drafts are draft documents valid for a maximum of six
months and may be updated, replaced, or obsoleted by other documents months and may be updated, replaced, or obsoleted by other documents
at any time. It is inappropriate to use Internet-Drafts as at any time. It is inappropriate to use Internet-Drafts as
reference material or to cite them other than as "work in progress". reference material or to cite them other than as "work in progress".
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Internet Message Access Protocol (IMAP) version 4rev1 has basic Internet Message Access Protocol (IMAP) version 4rev1 has basic
support for non-ASCII characters in mailbox names and search support for non-ASCII characters in mailbox names and search
substrings. It also supports non-ASCII message headers and content substrings. It also supports non-ASCII message headers and content
encoded as specified by Multipurpose Internet Mail Extensions encoded as specified by Multipurpose Internet Mail Extensions
(MIME). This specification defines a collection of IMAP extensions (MIME). This specification defines a collection of IMAP extensions
which improve international support including comparator negotiation which improve international support including comparator negotiation
for search, sort and thread, language negotiation for international for search, sort and thread, language negotiation for international
error text, and translations for namespace prefixes. error text, and translations for namespace prefixes.
Internet-draft June 2004 Internet-draft October 2004
Table of Contents Table of Contents
1. Conventions Used in this Document . . . . . . . . . . . . . . 3 1. Conventions Used in this Document . . . . . . . . . . . . . . 3
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
3. LANGUAGE Extension . . . . . . . . . . . . . . . . . . . . . 3 3. LANGUAGE Extension . . . . . . . . . . . . . . . . . . . . . 3
3.1 LANGUAGE Extension Requirements . . . . . . . . . . . . . . . 3 3.1 LANGUAGE Extension Requirements . . . . . . . . . . . . . . . 3
3.2 LANGUAGE Command . . . . . . . . . . . . . . . . . . . . . . 4 3.2 LANGUAGE Command . . . . . . . . . . . . . . . . . . . . . . 4
3.3 LANGUAGE Response . . . . . . . . . . . . . . . . . . . . . . 5 3.3 LANGUAGE Response . . . . . . . . . . . . . . . . . . . . . . 5
3.4 TRANSLATION Extension to the NAMESPACE Response . . . . . . . 6 3.4 TRANSLATION Extension to the NAMESPACE Response . . . . . . . 6
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Intellectual Property and Copyright Statements . . . . . . . 16 Intellectual Property and Copyright Statements . . . . . . . 16
Conventions Used in This Document Conventions Used in This Document
The key words "MUST", "MUST NOT", "SHOULD", "SHOULD NOT", and "MAY" The key words "MUST", "MUST NOT", "SHOULD", "SHOULD NOT", and "MAY"
in this document are to be interpreted as defined in "Key words for in this document are to be interpreted as defined in "Key words for
use in RFCs to Indicate Requirement Levels" [1]. use in RFCs to Indicate Requirement Levels" [1].
The formal syntax use the Augmented Backus-Naur Form (ABNF) [2] The formal syntax use the Augmented Backus-Naur Form (ABNF) [2]
notation including the core rules defined in Appendix A of RFC 2234. notation including the core rules defined in Appendix A of RFC 2234.
The UTF8-related productions are defined in RFC 3629 [7].
In examples, "C:" and "S:" indicate lines sent by the client and In examples, "C:" and "S:" indicate lines sent by the client and
server respectively. If a single "C:" or "S:" label applies to server respectively. If a single "C:" or "S:" label applies to
multiple lines, then the line breaks between those lines are for multiple lines, then the line breaks between those lines are for
editorial clarity only and are not part of the actual protocol editorial clarity only and are not part of the actual protocol
exchange. exchange.
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2. Introduction 2. Introduction
This specification defines two IMAP4rev1 [6] extensions to enhance This specification defines two IMAP4rev1 [6] extensions to enhance
international support. These extensions can be advertised and international support. These extensions can be advertised and
implemented separately. implemented separately.
The LANGUAGE extension allows the client to request a suitable The LANGUAGE extension allows the client to request a suitable
language for protocol error messages and in combination with the language for protocol error messages and in combination with the
NAMESPACE extension [4] enables namespace translations. NAMESPACE extension [4] enables namespace translations.
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CAPABILITY data. CAPABILITY data.
A server that advertises this extension MUST use the language "i- A server that advertises this extension MUST use the language "i-
default" as described in [3] as its default language until another default" as described in [3] as its default language until another
supported language is negotiated by the client. A server MUST supported language is negotiated by the client. A server MUST
include "i-default" as one of its supported languages. include "i-default" as one of its supported languages.
A client that supports this extension MUST be prepared for a A client that supports this extension MUST be prepared for a
possible NAMESPACE response [4] from the server. possible NAMESPACE response [4] from the server.
The LANGUAGE command is valid in not-authenticated, authenticated The LANGUAGE command is valid in all states.
and selected states.
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3.2 LANGUAGE Command 3.2 LANGUAGE Command
Arguments: Optional language range argument. Arguments: Optional language range argument.
Response: A possible LANGUAGE response (see Section 3.3). Response: A possible LANGUAGE response (see Section 3.3).
A possible NAMESPACE response as defined by [4]. A possible NAMESPACE response as defined by [4].
Result: OK - Command completed Result: OK - Command completed
NO - Could not complete command NO - Could not complete command
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it MAY return a tagged NO response to the enumeration request. it MAY return a tagged NO response to the enumeration request.
< The server defaults to using English i-default responses until < The server defaults to using English i-default responses until
the user explicitly changes the language. > the user explicitly changes the language. >
C: A001 LOGIN KAREN PASSWORD C: A001 LOGIN KAREN PASSWORD
S: A001 OK LOGIN completed S: A001 OK LOGIN completed
< Client requested MUL language. Server MUST reply with BAD. > < Client requested MUL language. Server MUST reply with BAD. >
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C: A002 LANGUAGE MUL C: A002 LANGUAGE MUL
S: A002 BAD Invalid language MUL S: A002 BAD Invalid language MUL
< A LANGUAGE command with no arguments is a request to enumerate < A LANGUAGE command with no arguments is a request to enumerate
the list of languages the server supports. > the list of languages the server supports. >
C: A003 LANGUAGE C: A003 LANGUAGE
S: * LANGUAGE (EN DE IT i-default) S: * LANGUAGE (EN DE IT i-default)
S: A003 OK Supported languages have been enumerated S: A003 OK Supported languages have been enumerated
C: B001 LANGUAGE C: B001 LANGUAGE
S: B001 NO Server is unable to enumerate supported languages S: B001 NO Server is unable to enumerate supported languages
< Once the client changes the language, all responses will be in < Once the client changes the language, all responses will be in
that language starting with the tagged OK to the LANGUAGE that language starting with the tagged OK to the LANGUAGE
command. > command. Because RFCs are in US-ASCII, this document uses an
ASCII transcription rather than UTF-8 text, e.g. ue in the
word "ausgefuehrt" >
C: A004 LANGUAGE FR C: A004 LANGUAGE DE
S: A004 OK La Language commande a ete execute avec success S: A004 OK Sprachwechsel durch LANGUAGE-Befehl ausgefuehrt
< If a server does not support the requested primary language, < If a server does not support the requested primary language,
responses will continue to be returned in the current language responses will continue to be returned in the current language
the server is using. > the server is using. >
C: A005 LANGUAGE DE C: A005 LANGUAGE FR
S: A005 NO Ce Language n'est pas supporte S: A005 NO Diese Sprache ist nicht unterstuetzt
C: A006 LANGUAGE FR-CA C: A006 LANGUAGE DE-IT
S: * LANGUAGE (FR-CA) S: * LANGUAGE (DE-IT)
S: A006 OK La Language commande a ete execute avec success S: A006 OK Sprachwechsel durch LANGUAGE-Befehl ausgefuehrt
C: A007 LANGUAGE "*" C: A007 LANGUAGE "*"
S: * LANGUAGE (FR) S: * LANGUAGE (DE)
S: A007 OK La Language commande a ete execute avec success S: A007 OK LANGUAGE-Befehl erfolgreich ausgefuehrt
3.3 LANGUAGE Response 3.3 LANGUAGE Response
Contents: A list of one or more language tags. Contents: A list of one or more language tags.
The LANGUAGE response occurs as a result of a LANGUAGE command. A The LANGUAGE response occurs as a result of a LANGUAGE command. A
LANGUAGE response with a list containing a single language tag LANGUAGE response with a list containing a single language tag
indicates that the server is now using that language. A LANGUAGE indicates that the server is now using that language. A LANGUAGE
response with a list containing multiple language tags indicates the response with a list containing multiple language tags indicates the
server is communicating a list of available languages to the client, server is communicating a list of available languages to the client,
and no change in the active language has been made. and no change in the active language has been made.
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3.4 TRANSLATION Extension to the NAMESPACE Response 3.4 TRANSLATION Extension to the NAMESPACE Response
If the server supports the IMAP4 NAMESPACE command [4], the server If the server supports the IMAP4 NAMESPACE command [4], the server
MUST return an untagged NAMESPACE response when a language is MUST return an untagged NAMESPACE response when a language is
negotiated. However the server MUST NOT return a NAMESPACE response negotiated. However the server MUST NOT return a NAMESPACE response
if it is in not-authenticated state. if it is in not-authenticated state.
If as a result of the newly negotiated language, localized If as a result of the newly negotiated language, localized
representations of the namespace prefixes are available, the server representations of the namespace prefixes are available, the server
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between the namespace prefix and the translation of the namespace between the namespace prefix and the translation of the namespace
prefix when presenting mailbox names to the user. prefix when presenting mailbox names to the user.
In this example a server supports the IMAP4 NAMESPACE command. It In this example a server supports the IMAP4 NAMESPACE command. It
uses no prefix to the user's Personal Namespace, a prefix of "Other uses no prefix to the user's Personal Namespace, a prefix of "Other
Users" to its Other Users' Namespace and a prefix of "Public Users" to its Other Users' Namespace and a prefix of "Public
Folders" to its only Shared Namespace. Since a client will often Folders" to its only Shared Namespace. Since a client will often
display these prefixes to the user, the server includes a display these prefixes to the user, the server includes a
translation of them that can be presented to the user. translation of them that can be presented to the user.
C: A001 LANGUAGE FR-CA C: A001 LANGUAGE DE-IT
S: * NAMESPACE (("" "/"))(("Other Users/" "/" "TRANSLATION" S: * NAMESPACE (("" "/"))(("Other Users/" "/" "TRANSLATION"
("Autres Utilisateurs/"))) (("Public Folders/" "/" ("Andere Ben&APw-tzer/"))) (("Public Folders/" "/"
"TRANSLATION" ("R&Aok-pertoires Publics/"))) "TRANSLATION" ("Gemeinsame Mailboxen/")))
S: A001 OK La Language commande a ete executee avec success S: A001 OK La Language commande a ete executee avec success
3.5 Formal Syntax 3.5 Formal Syntax
The following syntax specification inherits ABNF [2] rules from The following syntax specification inherits ABNF [2] rules from
IMAP4rev1 [6], IMAP4 Namespace [4], Tags for the Identification of IMAP4rev1 [6], IMAP4 Namespace [4], Tags for the Identification of
Languages [5], and UTF-8 [7]. Languages [5], and UTF-8 [7].
command-any =/ language-cmd command-any =/ language-cmd
; LANGUAGE command is valid in all states ; LANGUAGE command is valid in all states
language-cmd = "LANGUAGE" [SP lang-range-quoted] language-cmd = "LANGUAGE" [SP lang-range-quoted]
language-data = "LANGUAGE" SP "(" lang-tag-quoted *(SP lang- language-data = "LANGUAGE" SP "(" lang-tag-quoted *(SP lang-
tag-quoted) ")" tag-quoted) ")"
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namespace-trans = SP DQUOTE "TRANSLATION" DQUOTE SP "(" string namespace-trans = SP DQUOTE "TRANSLATION" DQUOTE SP "(" string
")" ")"
; the string is encoded in Modified UTF-7. ; the string is encoded in Modified UTF-7.
; this is a subset of the syntax permitted by ; this is a subset of the syntax permitted by
; the Namespace_Response_Extension rule in RFC 2342 ; the Namespace_Response_Extension rule in RFC 2342
lang-range-quoted = astring lang-range-quoted = astring
; Once any literal wrapper or quoting is removed, this ; Once any literal wrapper or quoting is removed, this
; follows the language-range rule in section 2.5 of RFC 3066 ; follows the language-range rule in section 2.5 of RFC 3066
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The IMAP extension consists of a new command to determine or change The IMAP extension consists of a new command to determine or change
the active comparator and a new response to indicate the active the active comparator and a new response to indicate the active
comparator and possibly other available comparators. comparator and possibly other available comparators.
The term "default comparator" refers to the comparator which is used The term "default comparator" refers to the comparator which is used
by SEARCH and SORT absent any negotiation using the COMPARATOR by SEARCH and SORT absent any negotiation using the COMPARATOR
command. The term "active comparator" refers to the comparator command. The term "active comparator" refers to the comparator
which will be used within a session e.g. by SEARCH and SORT. The which will be used within a session e.g. by SEARCH and SORT. The
COMPARATOR command is used to change the active comparator. COMPARATOR command is used to change the active comparator.
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The active comparator applies to the following SEARCH keys: "BCC", The active comparator applies to the following SEARCH keys: "BCC",
"BODY", "CC", "FROM", "SUBJECT", "TEXT", "TO" and "HEADER". If the "BODY", "CC", "FROM", "SUBJECT", "TEXT", "TO" and "HEADER". If the
server also advertises the "SORT" extension, then the active server also advertises the "SORT" extension, then the active
comparator applies to the following SORT keys: "CC", "FROM", comparator applies to the following SORT keys: "CC", "FROM",
"SUBJECT" and "TO". If the server advertises the "SUBJECT" and "TO". If the server advertises the
THREAD=ORDEREDSUBJECT, then the active comparator applies to the THREAD=ORDEREDSUBJECT, then the active comparator applies to the
ORDEREDSUBJECT threading algorithm. ORDEREDSUBJECT threading algorithm. Future extensions may choose to
apply the active comparator to their SEARCH keys.
For SORT and THREAD, the pre-processing necessary to extract the For SORT and THREAD, the pre-processing necessary to extract the
base subject text from a Subject header occurs prior to the base subject text from a Subject header occurs prior to the
application of a comparator. application of a comparator.
4.1 COMPARATOR Extension Requirements 4.1 COMPARATOR Extension Requirements
IMAP servers that support this extension MUST list the keyword IMAP servers that support this extension MUST list the keyword
COMPARATOR in their CAPABILITY data once IMAP enters authenticated COMPARATOR in their CAPABILITY data once IMAP enters authenticated
state, and MAY list that keyword in other states. state, and MAY list that keyword in other states.
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administrator, and MAY be sensitive to the current user. Once the administrator, and MAY be sensitive to the current user. Once the
IMAP connection enters authenticated state, the default comparator IMAP connection enters authenticated state, the default comparator
MUST remain static for the remainder of that connection. MUST remain static for the remainder of that connection.
A server that advertises this extension MUST support UTF-8 as a A server that advertises this extension MUST support UTF-8 as a
SEARCH charset. SEARCH charset.
The COMPARATOR command is valid in authenticated and selected The COMPARATOR command is valid in authenticated and selected
states. states.
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4.2 Comparators and Charsets 4.2 Comparators and Charsets
For SEARCH, SORT and THREAD operations that apply to message For SEARCH, SORT and THREAD operations that apply to message
headers, the server is responsible for removing the MIME header headers, the server is responsible for removing the MIME header
encoding [10] and converting the text of any known charsets to UTF-8 encoding [10] and converting the text of any known charsets to UTF-8
prior to applying the comparator algorithm. Unknown charsets should prior to applying the comparator algorithm. Unknown charsets should
never match when using the SEARCH command, and should sort together never match when using the SEARCH command, and should sort together
with invalid comparator input for the SORT and THREAD commands. with invalid comparator input for the SORT and THREAD commands.
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< The client requests activating a Czech comparator if possible, < The client requests activating a Czech comparator if possible,
or else a generic international comparator which it considers or else a generic international comparator which it considers
suitable for Czech. The server picks the first supported suitable for Czech. The server picks the first supported
comparator. > comparator. >
C: A001 COMPARATOR cz;* i;basic* C: A001 COMPARATOR cz;* i;basic*
S: * COMPARATOR i;basic;uca=3.1.1;uv=3.2 S: * COMPARATOR i;basic;uca=3.1.1;uv=3.2
S: A001 OK Will use i;basic;uca=3.1.1;uv=3.2 for collation S: A001 OK Will use i;basic;uca=3.1.1;uv=3.2 for collation
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< The client requests pure octet matching, then does a search < The client requests pure octet matching, then does a search
for potential GIF files, then switches back to its usual for potential GIF files, then switches back to its usual
comparator. > comparator. >
C: B123 COMPARATOR i;octet C: B123 COMPARATOR i;octet
S: * COMPARATOR i;octet S: * COMPARATOR i;octet
S: B123 OK S: B123 OK
C: B124 SEARCH OR BODY GIF87A BODY GIF89A C: B124 SEARCH OR BODY GIF87A BODY GIF89A
S: * SEARCH 42 69 S: * SEARCH 42 69
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comparator-cmd = "COMPARATOR" *(SP comp-order-quoted) comparator-cmd = "COMPARATOR" *(SP comp-order-quoted)
comparator-data = "COMPARATOR" SP comp-sel-quoted [SP "(" comparator-data = "COMPARATOR" SP comp-sel-quoted [SP "("
comp-name-quoted *(SP comp-name-quoted) ")"] comp-name-quoted *(SP comp-name-quoted) ")"]
comp-name-quoted = astring comp-name-quoted = astring
; Once any literal wrapper or quoting is removed, ; Once any literal wrapper or quoting is removed,
; this follows the comparator-name rule ; this follows the comparator-name rule
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comp-order-quoted = astring comp-order-quoted = astring
; Once any literal wrapper or quoting is removed, ; Once any literal wrapper or quoting is removed,
; this follows the comparator-order rule ; this follows the comparator-order rule
comp-sel-quoted = astring comp-sel-quoted = astring
; Once any literal wrapper or quoting is removed, ; Once any literal wrapper or quoting is removed,
; this follows the comparator-sel rule ; this follows the comparator-sel rule
5. Other IMAP Internationalization Issues 5. Other IMAP Internationalization Issues
The following sections provide an overview of various other IMAP The following sections provide an overview of various other IMAP
internationalization issues. These issues are not resolved by this internationalization issues. These issues are not resolved by this
specification, but could be resolved by future standards work. specification, but could be resolved by future standards work.
5.1 UTF-8 Userids and Passwords 5.1 UTF-8 Userids and Passwords
IMAP4rev1 presently restricts the userid and password fields of the IMAP4rev1 presently restricts the userid and password fields of the
LOGIN command to US-ASCII. Because the ability to enter a userid LOGIN command to US-ASCII. Because the ability to enter a userid
and password is necessary to use IMAP at all for most authentication and password is necessary to use IMAP at all for most authentication
mechanisms, the potential lack of input methods for non-ASCII text mechanisms, the potential inability to enter userid and password
is a serious interoperability concern. However, because of the with some clients is a serious interoperability concern. However,
visibility of these fields to end-users, it is expected that because of the visibility of these fields to end-users, it is
pressure to support UTF-8 login names and passwords will eventually expected that supporting unicode login names and passwords will
become irresistable. This specification defers such work until the eventually be practical and necessary.
SASL-related profile of stringprep [12] is published as an RFC, and
the impact on ACLs and email addresses has been assessed. This has been left out of this document, because the SASL-related
profile of stringprep [12] has not yet been published as an RFC, and
the impact on ACLs and email addresses has not been assessed.
The "userid" and "password" fields of the IMAP LOGIN command are The "userid" and "password" fields of the IMAP LOGIN command are
restricted to US-ASCII only until a future standards track RFC restricted to US-ASCII only until a future standards track RFC
states otherwise. Servers are encouraged to validate both fields to states otherwise. Servers are encouraged to validate both fields to
make sure they conform to the formal syntax of UTF-8 and to reject make sure they conform to the formal syntax of UTF-8 and to reject
the LOGIN command if that syntax is violated. Servers MAY reject the LOGIN command if that syntax is violated. Servers MAY reject
the use of any 8-bit in the "userid" or "password" field. the use of any 8-bit in the "userid" or "password" field.
5.2 UTF-8 Mailbox Names 5.2 UTF-8 Mailbox Names
The modified UTF-7 mailbox naming convention described in section The modified UTF-7 mailbox naming convention described in section
5.1.3 of RFC 3501 is best viewed as an transition from the status 5.1.3 of RFC 3501 is best viewed as an transition from the status
quo in 1996 when modified UTF-7 was first specified. At that time, quo in 1996 when modified UTF-7 was first specified. At that time,
there was widespread unofficial use of local character sets such as there was widespread unofficial use of local character sets such as
ISO-8859-1 and Shift-JIS for non-ASCII mailbox names, with resultant ISO-8859-1 and Shift-JIS for non-ASCII mailbox names, with resultant
non-interoperability. non-interoperability.
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The requirements in section 5.1 of RFC 3501 are very important if The requirements in section 5.1 of RFC 3501 are very important if
we're ever going to be able to deploy UTF-8 mailbox names. Servers we're ever going to be able to deploy UTF-8 mailbox names. Servers
are encourated to enforce them. are encourated to enforce them.
5.3 UTF-8 Domains, Addresses and Mail Headers 5.3 UTF-8 Domains, Addresses and Mail Headers
There is now an IETF standard for Internationalizing Domain Names in There is now an IETF standard for Internationalizing Domain Names in
Applications [13]. While IMAP clients are free to support this Applications [13]. While IMAP clients are free to support this
standard and convert punycode [14] to UTF-8 at display time, an standard, an argument can be made that it would be helpful to simple
argument can be made that it would be helpful to simple clients if clients if the IMAP server could perform this conversion (the same
the IMAP server could perform this conversion (the same argument argument would apply to MIME header encoding [10]). However, it
would apply to MIME header encoding [10]). However, it would be would be unwise to move forward with such work until the work in
unwise to move forward with such work until the work in progress to progress to define the format of international email addresses is
define the format of international email addresses is complete. complete.
6. IANA Considerations 6. IANA Considerations
When this is published as an RFC, the IMAP extensions LANGUAGE and When this is published as an RFC, the IMAP extensions LANGUAGE and
COMPARATOR are registered. COMPARATOR are registered.
7. Security Considerations 7. Security Considerations
The LANGUAGE extension makes a new command available in "Not The LANGUAGE extension makes a new command available in "Not
Authenticated" state in IMAP. Some IMAP implementations run with Authenticated" state in IMAP. Some IMAP implementations run with
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more difficult to interpret. This is not a new attack as the error more difficult to interpret. This is not a new attack as the error
messages themselves are subject to active attack. Clients MUST re- messages themselves are subject to active attack. Clients MUST re-
issue the LANGUAGE command once a security layer is active, so this issue the LANGUAGE command once a security layer is active, so this
does not impact subsequent protocol operations. does not impact subsequent protocol operations.
Both the LANGUAGE and COMPARATOR extensions use the UTF-8 charset, Both the LANGUAGE and COMPARATOR extensions use the UTF-8 charset,
thus the security considerations for UTF-8 [7] are relevent. thus the security considerations for UTF-8 [7] are relevent.
However, neither uses UTF-8 for identifiers so the most serious However, neither uses UTF-8 for identifiers so the most serious
concerns do not apply. concerns do not apply.
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8. Acknowledgements 8. Acknowledgements
The LANGUAGE extension is based on a previous Internet draft by Mike The LANGUAGE extension is based on a previous Internet draft by Mike
Gahrns and Alexey Melnikov, a substantial portion of the text in Gahrns and Alexey Melnikov, a substantial portion of the text in
that section was written by them. Many people have participated in that section was written by them. Many people have participated in
discussions about an IMAP Language extension in the various fora of discussions about an IMAP Language extension in the various fora of
the IETF and Internet working groups, so any list of contributors is the IETF and Internet working groups, so any list of contributors is
bound to be incomplete. However, the authors would like to thank bound to be incomplete. However, the authors would like to thank
Andrew McCown for early work on the original proposal, John Myers Andrew McCown for early work on the original proposal, John Myers
for suggestions regarding the namespace issue, along with Jutta for suggestions regarding the namespace issue, along with Jutta
Degener, Mark Crispin, Mark Pustilnik and Larry Osterman for their Degener, Mark Crispin, Mark Pustilnik, Larry Osterman and Martin
many suggestions that have been incorporated into this document. Duerst for their many suggestions that have been incorporated into
this document.
Initial discussion of the COMPARATOR extension involved input from Initial discussion of the COMPARATOR extension involved input from
Mark Crispin and other participants of the IMAP Extensions WG. Mark Crispin and other participants of the IMAP Extensions WG.
9. Relevant Standards for i18n IMAP Implementations 9. Relevant Standards for i18n IMAP Implementations
This is a non-normative list of standards to consider when This is a non-normative list of standards to consider when
implementing i18n aware IMAP software. implementing i18n aware IMAP software.
o The LANGUAGE and COMPARATOR extensions to IMAP (this o The LANGUAGE and COMPARATOR extensions to IMAP (this
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o MIME Parameter Value and Encoded Word Extensions [11] for o MIME Parameter Value and Encoded Word Extensions [11] for
filenames. Quality IMAP server implementations will filenames. Quality IMAP server implementations will
automatically combine multipart parameters when generating the automatically combine multipart parameters when generating the
BODYSTRUCTURE. There is also some deployed non-standard use of BODYSTRUCTURE. There is also some deployed non-standard use of
MIME header encoding inside double-quotes for filenames. MIME header encoding inside double-quotes for filenames.
o IDNA [13] and punycode [14] for domain names (presently only o IDNA [13] and punycode [14] for domain names (presently only
relevant to IMAP clients). relevant to IMAP clients).
o The UTF-8 charset [7]. o The UTF-8 charset [7].
o The IETF policy on Character Sets and Languages [3]. o The IETF policy on Character Sets and Languages [3].
Internet-draft June 2004 Internet-draft October 2004
Normative References Normative References
[1] Bradner, S., "Key words for use in RFCs to Indicate Requirement [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997. Levels", BCP 14, RFC 2119, March 1997.
[2] Crocker, D. and P. Overell, "Augmented BNF for Syntax [2] Crocker, D. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", RFC 2234, November 1997. Specifications: ABNF", RFC 2234, November 1997.
[3] Alvestrand, H., "IETF Policy on Character Sets and Languages", [3] Alvestrand, H., "IETF Policy on Character Sets and Languages",
skipping to change at page 14, line 31 skipping to change at page 14, line 31
[5] Alvestrand, H., "Tags for the Identification of Languages", BCP [5] Alvestrand, H., "Tags for the Identification of Languages", BCP
47, RFC 3066, January 2001. 47, RFC 3066, January 2001.
[6] Crispin, M., "INTERNET MESSAGE ACCESS PROTOCOL - VERSION [6] Crispin, M., "INTERNET MESSAGE ACCESS PROTOCOL - VERSION
4rev1", RFC 3501, March 2003. 4rev1", RFC 3501, March 2003.
[7] Yergeau, F., "UTF-8, a transformation format of ISO 10646", STD [7] Yergeau, F., "UTF-8, a transformation format of ISO 10646", STD
63, RFC 3629, November 2003. 63, RFC 3629, November 2003.
[8] Newman, C., "Internet Application Protocol Comparator [8] Newman, C., "Internet Application Protocol Comparator
Registry", draft-newman-i18n-comparator-01 (work in progress), Registry", draft-newman-i18n-comparator-02 (work in progress),
October 2003. This draft has expired; a new draft will be July 2004.
published by Ned Freed.
Informative References Informative References
[9] Freed, N. and N. Borenstein, "Multipurpose Internet Mail [9] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) Part One: Format of Internet Message Bodies", Extensions (MIME) Part One: Format of Internet Message Bodies",
RFC 2045, November 1996. RFC 2045, November 1996.
[10] Moore, K., "MIME (Multipurpose Internet Mail Extensions) Part [10] Moore, K., "MIME (Multipurpose Internet Mail Extensions) Part
Three: Message Header Extensions for Non-ASCII Text", RFC 2047, Three: Message Header Extensions for Non-ASCII Text", RFC 2047,
November 1996. November 1996.
skipping to change at page 15, line 5 skipping to change at page 15, line 5
[11] Freed, N. and K. Moore, "MIME Parameter Value and Encoded Word [11] Freed, N. and K. Moore, "MIME Parameter Value and Encoded Word
Extensions: Character Sets, Languages, and Continuations", RFC Extensions: Character Sets, Languages, and Continuations", RFC
2231, November 1997. 2231, November 1997.
[12] Hoffman, P. and M. Blanchet, "Preparation of Internationalized [12] Hoffman, P. and M. Blanchet, "Preparation of Internationalized
Strings ("stringprep")", RFC 3454, December 2002. Strings ("stringprep")", RFC 3454, December 2002.
[13] Faltstrom, P., Hoffman, P. and A. Costello, "Internationalizing [13] Faltstrom, P., Hoffman, P. and A. Costello, "Internationalizing
Domain Names in Applications (IDNA)", RFC 3490, March 2003. Domain Names in Applications (IDNA)", RFC 3490, March 2003.
Internet-draft June 2004 Internet-draft October 2004
[14] Costello, A., "Punycode: A Bootstring encoding of Unicode for [14] Costello, A., "Punycode: A Bootstring encoding of Unicode for
Internationalized Domain Names in Applications (IDNA)", RFC Internationalized Domain Names in Applications (IDNA)", RFC
3492, March 2003. 3492, March 2003.
[15] Crispin, M. and K. Murchison, "INTERNET MESSAGE ACCESS PROTOCOL [15] Crispin, M. and K. Murchison, "INTERNET MESSAGE ACCESS PROTOCOL
- SORT AND THREAD EXTENSION", draft-ietf-imapext-sort-12 (work - SORT AND THREAD EXTENSION", draft-ietf-imapext-sort-17 (work
in progress), March 2003. in progress), May 2004.
[16] Daboo, C., "IMAP ANNOTATEMORE Extension", draft-daboo-imap- [16] Daboo, C., "IMAP ANNOTATEMORE Extension", draft-daboo-imap-
annotatemore-05 (work in progress), April 2004. annotatemore-05 (work in progress), April 2004.
Authors' Addresses Authors' Addresses
Chris Newman Chris Newman
Sun Microsystems Sun Microsystems
1050 Lakes Drive 1050 Lakes Drive
West Covina, CA 91790 West Covina, CA 91790
skipping to change at page 16, line 5 skipping to change at page 16, line 5
Oryx Mail Systems GmbH Oryx Mail Systems GmbH
Joseph-Dollinger-Bogen 14 Joseph-Dollinger-Bogen 14
D-80807 Muenchen D-80807 Muenchen
Germany Germany
Email: arnt@oryx.com Email: arnt@oryx.com
Phone: +49 89 32356-401 Phone: +49 89 32356-401
Fax: +49 89 32356-409 Fax: +49 89 32356-409
Internet-draft June 2004 Internet-draft October 2004
Intellectual Property Statement Intellectual Property Statement
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intellectual property or other rights that might be claimed to intellectual property or other rights that might be claimed to
pertain to the implementation or use of the technology described in pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights this document or the extent to which any license under such rights
might or might not be available; neither does it represent that it might or might not be available; neither does it represent that it
has made any effort to identify any such rights. Information on the has made any effort to identify any such rights. Information on the
IETF's procedures with respect to rights in standards-track and IETF's procedures with respect to rights in standards-track and
skipping to change at page 16, line 31 skipping to change at page 16, line 31
can be obtained from the IETF Secretariat. can be obtained from the IETF Secretariat.
The IETF invites any interested party to bring to its attention any The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary copyrights, patents or patent applications, or other proprietary
rights which may cover technology that may be required to practice rights which may cover technology that may be required to practice
this standard. Please address the information to the IETF Executive this standard. Please address the information to the IETF Executive
Director. Director.
Full Copyright Statement Full Copyright Statement
Copyright (C) The Internet Society (2003). All Rights Reserved. Copyright (C) The Internet Society (2004). This document is subject
to the rights, licenses and restrictions contained in BCP 78, and
This document and translations of it may be copied and furnished to except as set forth therein, the authors retain all their rights.
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Internet-draft June 2004
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF This document and the information contained herein are provided on
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 End of changes. 

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