draft-ietf-eai-rfc5337bis-dsn-04.txt   draft-ietf-eai-rfc5337bis-dsn-05.txt 
Network Working Group T. Hansen, Ed. Network Working Group T. Hansen, Ed.
Internet-Draft AT&T Laboratories Internet-Draft AT&T Laboratories
Obsoletes: 5337 (if approved) C. Newman Obsoletes: 5337 (if approved) C. Newman
Updates: 3461, 3462, 3464, 3798 Oracle Updates: 3461, 3462, 3464, 3798 Oracle
(if approved) A. Melnikov (if approved) A. Melnikov
Intended status: Standards Track Isode Ltd Intended status: Standards Track Isode Ltd
Expires: April 7, 2012 October 5, 2011 Expires: May 3, 2012 October 31, 2011
Internationalized Delivery Status and Disposition Notifications Internationalized Delivery Status and Disposition Notifications
draft-ietf-eai-rfc5337bis-dsn-04 draft-ietf-eai-rfc5337bis-dsn-05
Abstract Abstract
Delivery status notifications (DSNs) are critical to the correct Delivery status notifications (DSNs) are critical to the correct
operation of an email system. However, the existing Draft Standards operation of an email system. However, the existing Draft Standards
(RFC 3461, RFC 3462, RFC 3464) are presently limited to US-ASCII text (RFC 3461, RFC 3462, RFC 3464) are presently limited to US-ASCII text
in the machine-readable portions of the protocol. This specification in the machine-readable portions of the protocol. This specification
adds a new address type for international email addresses so an adds a new address type for international email addresses so an
original recipient address with non-US-ASCII characters can be original recipient address with non-US-ASCII characters can be
correctly preserved even after downgrading. This also provides correctly preserved even after downgrading. This also provides
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on April 7, 2012. This Internet-Draft will expire on May 3, 2012.
Copyright Notice Copyright Notice
Copyright (c) 2011 IETF Trust and the persons identified as the Copyright (c) 2011 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
skipping to change at page 2, line 22 skipping to change at page 2, line 22
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conventions Used in This Document . . . . . . . . . . . . . . 3 2. Conventions Used in This Document . . . . . . . . . . . . . . 3
3. UTF-8 Address Type . . . . . . . . . . . . . . . . . . . . . . 3 3. UTF-8 Address Type . . . . . . . . . . . . . . . . . . . . . . 3
4. UTF-8 Delivery Status Notifications . . . . . . . . . . . . . 6 4. UTF-8 Delivery Status Notifications . . . . . . . . . . . . . 6
4.1. Additional Requirements on SMTP Servers . . . . . . . . . 9 4.1. The message/global-delivery-status Media Type . . . . . . 6
4.2. The message/global Media Type . . . . . . . . . . . . . . 9
4.3. The message/global-headers Media Type . . . . . . . . . . 9
4.4. Using These Media Types with multipart/report . . . . . . 9
4.5. Additional Requirements on SMTP Servers . . . . . . . . . 9
5. UTF-8 Message Disposition Notifications . . . . . . . . . . . 10 5. UTF-8 Message Disposition Notifications . . . . . . . . . . . 10
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
6.1. UTF-8 Mail Address Type Registration . . . . . . . . . . . 11 6.1. UTF-8 Mail Address Type Registration . . . . . . . . . . . 11
6.2. Update to 'smtp' Diagnostic Type Registration . . . . . . 12 6.2. Update to 'smtp' Diagnostic Type Registration . . . . . . 12
6.3. message/global-headers . . . . . . . . . . . . . . . . . . 12 6.3. message/global-headers . . . . . . . . . . . . . . . . . . 12
6.4. message/global-delivery-status . . . . . . . . . . . . . . 13 6.4. message/global-delivery-status . . . . . . . . . . . . . . 14
6.5. message/global-disposition-notification . . . . . . . . . 14 6.5. message/global-disposition-notification . . . . . . . . . 15
7. Security Considerations . . . . . . . . . . . . . . . . . . . 16 7. Security Considerations . . . . . . . . . . . . . . . . . . . 16
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 16 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 17
8.1. Normative References . . . . . . . . . . . . . . . . . . . 16 8.1. Normative References . . . . . . . . . . . . . . . . . . . 17
8.2. Informative References . . . . . . . . . . . . . . . . . . 17 8.2. Informative References . . . . . . . . . . . . . . . . . . 18
Appendix A. Changes Since ... . . . . . . . . . . . . . . . . . . 18 Appendix A. Changes Since ... . . . . . . . . . . . . . . . . . . 18
A.1. Changes Since -00 . . . . . . . . . . . . . . . . . . . . 18 A.1. Changes Since -00 . . . . . . . . . . . . . . . . . . . . 18
A.2. Changes Since RFC 5337 . . . . . . . . . . . . . . . . . . 18 A.2. Changes Since RFC 5337 . . . . . . . . . . . . . . . . . . 19
Appendix B. Acknowledgements . . . . . . . . . . . . . . . . . . 18 Appendix B. Acknowledgements . . . . . . . . . . . . . . . . . . 19
1. Introduction 1. Introduction
When an email message is transmitted using the UTF8SMTP When an email message is transmitted using the UTF8SMTP
[I-D.ietf-eai-rfc5336bis] extension and Internationalized Email [I-D.ietf-eai-rfc5336bis] extension and Internationalized Email
Headers [I-D.ietf-eai-rfc5335bis], it is sometimes necessary to Headers [I-D.ietf-eai-rfc5335bis], it is sometimes necessary to
return that message or generate a Message Disposition Notification return that message or generate a Message Disposition Notification
(MDN) [RFC3798]. As a message sent to multiple recipients can (MDN) [RFC3798]. As a message sent to multiple recipients can
generate a status and disposition notification for each recipient, it generate a status and disposition notification for each recipient, it
is helpful if a client can correlate these notifications based on the is helpful if a client can correlate these notifications based on the
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the original recipient and updates the MDN and DSN formats to support the original recipient and updates the MDN and DSN formats to support
the new address types. the new address types.
NOTE: While this specification updates the experimental versions of NOTE: While this specification updates the experimental versions of
this protocol by removing certain constructs (e.g., the "<addr this protocol by removing certain constructs (e.g., the "<addr
<addr>>" address syntax is no longer permitted), the name of the <addr>>" address syntax is no longer permitted), the name of the
Address Type "UTF-8" and the media type names message/global, Address Type "UTF-8" and the media type names message/global,
message/global-delivery-status and message/global-headers have not message/global-delivery-status and message/global-headers have not
been changed. been changed.
This specification is a revision of and replacement for [RFC5337].
Section 6 of [I-D.ietf-eai-frmwrk-4952bis] describes the change in
approach between this specification and the previous version.
2. Conventions Used in This Document 2. Conventions Used in This Document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
The formal syntax use the Augmented Backus-Naur Form (ABNF) [RFC5234] The formal syntax uses the Augmented Backus-Naur Form (ABNF)
notation including the core rules defined in Appendix B of RFC 5234 [RFC5234] notation including the core rules defined in Appendix B of
[RFC5234] and the UTF-8 syntax rules in Section 4 of [RFC3629]. RFC 5234 [RFC5234] and the UTF-8 syntax rules in Section 4 of
[RFC3629].
3. UTF-8 Address Type 3. UTF-8 Address Type
An Extensible Message Format for Delivery Status Notifications An Extensible Message Format for Delivery Status Notifications
[RFC3464] defines the concept of an address type. The address format [RFC3464] defines the concept of an address type. The address format
introduced in Internationalized Email Headers introduced in Internationalized Email Headers
[I-D.ietf-eai-rfc5335bis] is a new address type. The syntax for the [I-D.ietf-eai-rfc5335bis] is a new address type. The syntax for the
new address type in the context of status notifications is specified new address type in the context of status notifications is specified
at the end of this section. at the end of this section.
An SMTP [RFC5321] server that advertises both the UTF8SMTP extension An SMTP [RFC5321] server that advertises both the UTF8SMTP extension
[I-D.ietf-eai-rfc5336bis] and the DSN extension [RFC3461] MUST accept [I-D.ietf-eai-rfc5336bis] and the DSN extension [RFC3461] MUST accept
a UTF-8 address type in the ORCPT parameter including 8-bit UTF-8 a UTF-8 address type in the ORCPT parameter including 8-bit UTF-8
characters. This address type also includes a 7-bit encoding characters. This address type also includes a 7-bit encoding
suitable for use in a message/delivery-status body part or an ORCPT suitable for use in a message/delivery-status body part or an ORCPT
parameter sent to an SMTP server that does not advertise UTF8SMTP. parameter sent to an SMTP server that does not advertise UTF8SMTP.
This address type has 3 forms: utf-8-addr-xtext, utf-8-addr-unitext, This address type has 3 forms: utf-8-addr-xtext, utf-8-addr-unitext,
and utf-8-address. Only the first form is 7-bit safe. and utf-8-address. Only the first form is 7-bit safe (only uses
7-bit characters).
The utf-8-address form is only suitable for use in newly defined The utf-8-address form is only suitable for use in newly defined
protocols capable of native representation of 8-bit characters. That protocols capable of native representation of 8-bit characters. That
is, the utf-8-address form MUST NOT be used in the ORCPT parameter is, the utf-8-address form MUST NOT be used in the ORCPT parameter
when the SMTP server doesn't advertise support for UTF8SMTP, or the when the SMTP server doesn't advertise support for UTF8SMTP, or the
SMTP server supports UTF8SMTP, but the address contains US-ASCII SMTP server supports UTF8SMTP, but the address contains US-ASCII
characters not permitted in the ORCPT parameter (e.g., the ORCPT characters not permitted in the ORCPT parameter (e.g., the ORCPT
parameter forbids unencoded SP and the = character), or in a 7-bit parameter forbids unencoded SP and the = character), or in a 7-bit
transport environment including a message/delivery-status Original- transport environment including a message/delivery-status Original-
Recipient or Final-Recipient field. In the first and third case, the Recipient or Final-Recipient field. In the first and third case, the
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NZDHEXDIG = %x31-39 / "A" / "B" / "C" / "E" / "F" NZDHEXDIG = %x31-39 / "A" / "B" / "C" / "E" / "F"
; HEXDIG excluding "0" and "D" ; HEXDIG excluding "0" and "D"
4. UTF-8 Delivery Status Notifications 4. UTF-8 Delivery Status Notifications
A traditional delivery status notification [RFC3464] comes in a A traditional delivery status notification [RFC3464] comes in a
three-part multipart/report [RFC3462] container, where the first part three-part multipart/report [RFC3462] container, where the first part
is human-readable text describing the error, the second part is a is human-readable text describing the error, the second part is a
7-bit-only message/delivery-status, and the optional third part is 7-bit-only message/delivery-status, and the optional third part is
used for content (message/rfc822) or header (text/rfc822-headers) used for content (message/rfc822) or header (text/rfc822-headers)
return. As the present DSN format does not permit returning of return. As the present standard DSN format does not permit the
undeliverable UTF8SMTP messages, three new media types are needed. return of undeliverable UTF8SMTP messages, three new media types are
needed. ([RFC5337] introduced experimental versions of these media
types.)
4.1. The message/global-delivery-status Media Type
The first type, message/global-delivery-status, has the syntax of The first type, message/global-delivery-status, has the syntax of
message/delivery-status with three modifications. First, the charset message/delivery-status with three modifications. First, the charset
for message/global-delivery-status is UTF-8, and thus any field MAY for message/global-delivery-status is UTF-8, and thus any field MAY
contain UTF-8 characters when appropriate (see the ABNF below). In contain UTF-8 characters when appropriate (see the ABNF below). In
particular, the Diagnostic-Code field MAY contain UTF-8 as described particular, the Diagnostic-Code field MAY contain UTF-8 as described
in UTF8SMTP [I-D.ietf-eai-rfc5336bis]; the Diagnostic-Code field in UTF8SMTP [I-D.ietf-eai-rfc5336bis]; the Diagnostic-Code field
SHOULD be in i-default language [RFC2277]. Second, systems SHOULD be in i-default language [RFC2277]. Second, systems
generating a message/global-delivery-status body part SHOULD use the generating a message/global-delivery-status body part SHOULD use the
utf-8-address form of the UTF-8 address type for all addresses utf-8-address form of the UTF-8 address type for all addresses
containing characters outside the US-ASCII repertoire. These systems containing characters outside the US-ASCII repertoire. These systems
SHOULD up-convert the utf-8-addr-xtext or the utf-8-addr-unitext form SHOULD up-convert the utf-8-addr-xtext or the utf-8-addr-unitext form
of a UTF-8 address type in the ORCPT parameter to the utf-8-address of a UTF-8 address type in the ORCPT parameter to the utf-8-address
form of a UTF-8 address type in the Original-Recipient field. Third, form of a UTF-8 address type in the Original-Recipient field. Third,
a new optional field called Localized-Diagnostic is added. Each an optional field called Localized-Diagnostic is added. Each
instance includes a language tag [RFC5646] and contains text in the instance includes a language tag [RFC5646] and contains text in the
specified language. This is equivalent to the text part of the specified language. This is equivalent to the text part of the
Diagnostic-Code field. All instances of Localized-Diagnostic MUST Diagnostic-Code field. All instances of Localized-Diagnostic MUST
use different language tags. The ABNF for message/ use different language tags. The ABNF for message/
global-delivery-status is specified below. global-delivery-status is specified below.
In the ABNF below, all productions not defined in this document are In the ABNF below, all productions not defined in this document are
defined in Appendix B of [RFC5234], in Section 4 of [RFC3629], or in defined in Appendix B of [RFC5234], in Section 4 of [RFC3629], or in
[RFC3464]. Note that <text-fixed> is the same as <text> from [RFC3464]. Note that <text-fixed> is the same as <text> from
[RFC5322], but without <obs-text>. If or when RFC 5322 is updated to [RFC5322], but without <obs-text>. If or when RFC 5322 is updated to
disallow <obs-text>, this should become just <text> Also, if or when disallow <obs-text>, this should become just <text>. Also, if or
RFC 5322 is updated to disallow control characters in <text>, this when RFC 5322 is updated to disallow control characters in <text>,
should become a reference to that update instead. this should become a reference to that update instead.
utf-8-delivery-status-content = per-message-fields utf-8-delivery-status-content = per-message-fields
1*( CRLF utf-8-per-recipient-fields ) 1*( CRLF utf-8-per-recipient-fields )
; "per-message-fields" remains unchanged from the definition ; "per-message-fields" remains unchanged from the definition
; in RFC 3464, except for the "extension-field" ; in RFC 3464, except for the "extension-field"
; which is updated below. ; which is updated below.
utf-8-per-recipient-fields = utf-8-per-recipient-fields =
[ original-recipient-field CRLF ] [ original-recipient-field CRLF ]
final-recipient-field CRLF final-recipient-field CRLF
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; Updates Section 7 of RFC3798 ; Updates Section 7 of RFC3798
text-fixed = %d1-9 / ; Any US-ASCII character except for NUL, text-fixed = %d1-9 / ; Any US-ASCII character except for NUL,
%d11 / ; CR and LF %d11 / ; CR and LF
%d12 / ; See note above about <text-fixed> %d12 / ; See note above about <text-fixed>
%d14-127 %d14-127
utf8-text = text-fixed / UTF8-non-ascii utf8-text = text-fixed / UTF8-non-ascii
UTF8-non-ascii = UTF8-2 / UTF8-3 / UTF8-4 UTF8-non-ascii = UTF8-2 / UTF8-3 / UTF8-4
4.2. The message/global Media Type
The second type, used for returning the content, is message/global The second type, used for returning the content, is message/global
which is similar to message/rfc822, except it contains a message with which is similar to message/rfc822, except it contains a message with
UTF-8 headers. This media type is described in UTF-8 headers. This media type is described in
[I-D.ietf-eai-rfc5335bis]. [I-D.ietf-eai-rfc5335bis].
4.3. The message/global-headers Media Type
The third type, used for returning the headers, is message/ The third type, used for returning the headers, is message/
global-headers and contains only the UTF-8 header fields of a message global-headers and contains only the UTF-8 header fields of a message
(all lines prior to the first blank line in a UTF8SMTP message). (all lines prior to the first blank line in a UTF8SMTP message).
Unlike message/global, this body part provides no difficulties for Unlike message/global, this body part provides no difficulties for
the present infrastructure. the present infrastructure.
Note that as far as multipart/report [RFC3462] container is 4.4. Using These Media Types with multipart/report
Note that as far as a multipart/report [RFC3462] container is
concerned, message/global-delivery-status, message/global, and concerned, message/global-delivery-status, message/global, and
message/global-headers MUST be treated as equivalent to message/ message/global-headers MUST be treated as equivalent to message/
delivery-status, message/rfc822, and text/rfc822-headers. That is, delivery-status, message/rfc822, and text/rfc822-headers. That is,
implementations processing multipart/report MUST expect any implementations processing multipart/report MUST expect any
combinations of the 6 media types mentioned above inside a multipart/ combinations of the 6 media types mentioned above inside a multipart/
report media type. report media type.
All three new types will typically use the "8bit" Content-Transfer- All three new types will typically use the "8bit" Content-Transfer-
Encoding. (In the event all content is 7-bit, the equivalent Encoding. (In the event all content is 7-bit, the equivalent
traditional types for delivery status notifications MAY be used. For traditional types for delivery status notifications MAY be used. For
example, if information in message/global-delivery-status part can be example, if information in message/global-delivery-status part can be
represented without any loss of information as message/ represented without any loss of information as message/
delivery-status, then the message/delivery-status body part may be delivery-status, then the message/delivery-status body part may be
used.) Note that [I-D.ietf-eai-rfc5335bis] relaxed restriction from used.) Note that [I-D.ietf-eai-rfc5335bis] relaxed a restriction
MIME [RFC2046] regarding use of Content-Transfer-Encoding in new from MIME [RFC2046] regarding the use of Content-Transfer-Encoding in
"message" subtypes. This specification explicitly allows use of new "message" subtypes. This specification explicitly allows the use
Content-Transfer-Encoding in message/global-headers and message/ of Content-Transfer-Encoding in message/global-headers and message/
global-delivery-status. This is not believed to be problematic as global-delivery-status. This is not believed to be problematic as
these new media types are intended primarily for use by newer systems these new media types are intended primarily for use by newer systems
with full support for 8-bit MIME and UTF-8 headers. with full support for 8-bit MIME and UTF-8 headers.
4.1. Additional Requirements on SMTP Servers 4.5. Additional Requirements on SMTP Servers
If an SMTP server that advertises both UTF8SMTP and DSN needs to If an SMTP server that advertises both UTF8SMTP and DSN needs to
return an undeliverable UTF8SMTP message, then it has two choices for return an undeliverable UTF8SMTP message, then it has two choices for
encapsulating the UTF8SMTP message when generating the corresponding encapsulating the UTF8SMTP message when generating the corresponding
multipart/report: multipart/report:
If the return path SMTP server does not support UTF8SMTP, then the If the return path SMTP server does not support UTF8SMTP, then the
undeliverable body part and headers MUST be encoded using a 7-bit undeliverable body part and headers MUST be encoded using a 7-bit
Content-Transfer-Encoding such as "base64" or "quoted-printable" Content-Transfer-Encoding such as "base64" or "quoted-printable"
[RFC2045], as detailed in Section 4. [RFC2045], as detailed in Section 4.
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simply correlating message-IDs may be sufficient to distinguish true simply correlating message-IDs may be sufficient to distinguish true
status notifications from those resulting from forged originator status notifications from those resulting from forged originator
addresses. But in the longer term, including cryptographic signature addresses. But in the longer term, including cryptographic signature
material that can securely associate the status notification with the material that can securely associate the status notification with the
original message is advisable. original message is advisable.
As this specification permits UTF-8 in additional fields, the As this specification permits UTF-8 in additional fields, the
security considerations of UTF-8 [RFC3629] apply. security considerations of UTF-8 [RFC3629] apply.
8. References 8. References
8.1. Normative References 8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to [RFC2119] Bradner, S., "Key words for use in
Indicate Requirement Levels", BCP 14, RFCs to Indicate Requirement Levels",
RFC 2119, March 1997. BCP 14, RFC 2119, March 1997.
[RFC2277] Alvestrand, H., "IETF Policy on Character [RFC2277] Alvestrand, H., "IETF Policy on
Sets and Languages", BCP 18, RFC 2277, Character Sets and Languages", BCP 18,
January 1998. RFC 2277, January 1998.
[RFC3461] Moore, K., "Simple Mail Transfer Protocol [RFC3461] Moore, K., "Simple Mail Transfer
(SMTP) Service Extension for Delivery Protocol (SMTP) Service Extension for
Status Notifications (DSNs)", RFC 3461, Delivery Status Notifications (DSNs)",
January 2003. RFC 3461, January 2003.
[RFC3462] Vaudreuil, G., "The Multipart/Report [RFC3462] Vaudreuil, G., "The Multipart/Report
Content Type for the Reporting of Mail Content Type for the Reporting of Mail
System Administrative Messages", RFC 3462, System Administrative Messages",
January 2003. RFC 3462, January 2003.
[RFC3464] Moore, K. and G. Vaudreuil, "An Extensible [RFC3464] Moore, K. and G. Vaudreuil, "An
Message Format for Delivery Status Extensible Message Format for Delivery
Notifications", RFC 3464, January 2003. Status Notifications", RFC 3464,
January 2003.
[RFC3629] Yergeau, F., "UTF-8, a transformation [RFC3629] Yergeau, F., "UTF-8, a transformation
format of ISO 10646", STD 63, RFC 3629, format of ISO 10646", STD 63,
November 2003. RFC 3629, November 2003.
[RFC3798] Hansen, T. and G. Vaudreuil, "Message [RFC3798] Hansen, T. and G. Vaudreuil, "Message
Disposition Notification", RFC 3798, Disposition Notification", RFC 3798,
May 2004. May 2004.
[RFC5646] Phillips, A. and M. Davis, "Tags for [RFC5646] Phillips, A. and M. Davis, "Tags for
Identifying Languages", BCP 47, RFC 5646, Identifying Languages", BCP 47,
September 2009. RFC 5646, September 2009.
[RFC5321] Klensin, J., "Simple Mail Transfer [RFC5321] Klensin, J., "Simple Mail Transfer
Protocol", RFC 5321, October 2008. Protocol", RFC 5321, October 2008.
[RFC5322] Resnick, P., Ed., "Internet Message [RFC5322] Resnick, P., Ed., "Internet Message
Format", RFC 5322, October 2008. Format", RFC 5322, October 2008.
[RFC5234] Crocker, D. and P. Overell, "Augmented BNF [RFC5234] Crocker, D. and P. Overell, "Augmented
for Syntax Specifications: ABNF", STD 68, BNF for Syntax Specifications: ABNF",
RFC 5234, January 2008. STD 68, RFC 5234, January 2008.
[I-D.ietf-eai-rfc5335bis] Yang, A., Steele, S., and N. Freed, [I-D.ietf-eai-rfc5335bis] Yang, A., Steele, S., and N. Freed,
"Internationalized Email Headers", "Internationalized Email Headers",
draft-ietf-eai-rfc5335bis-12 (work in draft-ietf-eai-rfc5335bis-13 (work in
progress), September 2011. progress), October 2011.
[I-D.ietf-eai-rfc5336bis] Yao, J. and W. Mao, "SMTP Extension for [I-D.ietf-eai-rfc5336bis] Yao, J. and W. MAO, "SMTP Extension
Internationalized Email", for Internationalized Email",
draft-ietf-eai-rfc5336bis-13 (work in draft-ietf-eai-rfc5336bis-15 (work in
progress), September 2011. progress), October 2011.
8.2. Informative References [I-D.ietf-eai-frmwrk-4952bis] Klensin, J. and Y. Ko, "Overview and
Framework for Internationalized
Email",
draft-ietf-eai-frmwrk-4952bis-12 (work
in progress), October 2011.
[RFC2045] Freed, N. and N. Borenstein, "Multipurpose 8.2. Informative References
Internet Mail Extensions (MIME) Part One:
Format of Internet Message Bodies", [RFC2045] Freed, N. and N. Borenstein,
RFC 2045, November 1996. "Multipurpose Internet Mail Extensions
(MIME) Part One: Format of Internet
Message Bodies", RFC 2045,
November 1996.
[RFC2046] Freed, N. and N. Borenstein, "Multipurpose [RFC2046] Freed, N. and N. Borenstein,
Internet Mail Extensions (MIME) Part Two: "Multipurpose Internet Mail Extensions
Media Types", RFC 2046, November 1996. (MIME) Part Two: Media Types",
RFC 2046, November 1996.
[RFC5337] Newman, C. and A. Melnikov, [RFC5337] Newman, C. and A. Melnikov,
"Internationalized Delivery Status and "Internationalized Delivery Status and
Disposition Notifications", RFC 5337, Disposition Notifications", RFC 5337,
September 2008. September 2008.
Appendix A. Changes Since ... Appendix A. Changes Since ...
A.1. Changes Since -00 A.1. Changes Since -00
NOTE TO RFC EDITOR: Remove this section for publication. NOTE TO RFC EDITOR: Remove this section for publication.
Incorporated changes from draft-ietf-eai-dsnbis-01. Incorporated changes from draft-ietf-eai-dsnbis-01.
Fixed description of utf-8-addr-xtext and utf-8-addr-unitext. Fixed description of utf-8-addr-xtext and utf-8-addr-unitext.
 End of changes. 37 change blocks. 
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