Displaying Downgraded Messages for Email Address Internationalization
draft-ietf-eai-downgraded-display-03
The information below is for an old version of the document that is already published as an RFC.
| Document | Type | RFC Internet-Draft (eai WG) | |
|---|---|---|---|
| Authors | Barry Leiba , Kazunori Fujiwara | ||
| Last updated | 2015-10-14 (Latest revision 2009-12-01) | ||
| Replaces | draft-fujiwara-eai-downgraded-display | ||
| Stream | Internet Engineering Task Force (IETF) | ||
| Formats | plain text html xml htmlized pdfized bibtex | ||
| Reviews | |||
| Stream | WG state | WG Document | |
| Document shepherd | (None) | ||
| IESG | IESG state | RFC 5825 (Experimental) | |
| Consensus boilerplate | Unknown | ||
| Telechat date | (None) | ||
| Responsible AD | Alexey Melnikov | ||
| Send notices to | (None) |
draft-ietf-eai-downgraded-display-03
Email Address Internationalization K. Fujiwara
(EAI) JPRS
Internet-Draft B. Leiba
Intended status: Experimental Huawei Technologies
Expires: June 4, 2010 December 1, 2009
Displaying Downgraded Messages for Email Address Internationalization
draft-ietf-eai-downgraded-display-03.txt
Abstract
This document describes a method for displaying downgraded messages
which originally contained internationalized E-mail addresses or
internationalized header fields.
Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79.
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
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material or to cite them other than as "work in progress."
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This Internet-Draft will expire on June 4, 2010.
Copyright Notice
Copyright (c) 2009 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
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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 BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Converting downgraded message headers for display . . . . . . 3
3.1. Considerations . . . . . . . . . . . . . . . . . . . . . . 3
3.2. The process . . . . . . . . . . . . . . . . . . . . . . . 4
3.2.1. No reconstruction of the Envelope Information
Preservation Header Fields . . . . . . . . . . . . . . 4
3.2.2. Reconstructing the Address Header Fields'
Preservation Header Fields . . . . . . . . . . . . . . 4
3.2.3. The Unknown Header Fields' Preservation Header
Fields . . . . . . . . . . . . . . . . . . . . . . . . 5
4. Security considerations . . . . . . . . . . . . . . . . . . . 6
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 6
7. Change History . . . . . . . . . . . . . . . . . . . . . . . . 6
7.1. draft-fujiwara-eai-downgraded-display: Version 00 . . . . 7
7.2. draft-ietf-eai-downgraded-display: Version 00 . . . . . . 7
7.3. draft-ietf-eai-downgraded-display: Version 01 . . . . . . 7
7.4. draft-ietf-eai-downgraded-display: Version 02 . . . . . . 7
7.5. draft-ietf-eai-downgraded-display: Version 03 . . . . . . 7
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7
8.1. Normative References . . . . . . . . . . . . . . . . . . . 7
8.2. Informative References . . . . . . . . . . . . . . . . . . 8
Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 8
A.1. Displaying example . . . . . . . . . . . . . . . . . . . . 12
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 14
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1. Introduction
The Email Address Internationalization (UTF8SMTP) extension document
set [RFC4952] [RFC5336] [RFC5335] [RFC5337] expands Email address
structure, syntax and Email header format. To avoid rejection of
internationalized Email messages, the downgrading mechanism [RFC5504]
converts an internationalized message to a traditional Email message
when a server in the delivery path does not support the UTF8SMTP
extension. The downgraded message is a traditional Email message,
except the message has "Downgraded-" header fields.
A perfect reverse-function of the downgrading does not exist because
the encoding defined in [RFC2047] is not exactly reversible and
Received header field downgrading may remove FOR clause information.
The restoration of the downgrading should be done once at the final
destination of the downgraded message such as MUAs or IMAP servers.
This document describes the restoration methods for displaying
downgraded messages in MUAs.
2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
Specialized terms used in this specification are defined in the EAI
overview [RFC4952] or in [RFC5321][RFC5322], MIME documents [RFC2045]
[RFC2047] [RFC2183] [RFC2231].
This document depends on [RFC5335] and [RFC5504]. Key words used in
these document are used in this document, too.
The term "MIME decode" is used for both "encoded-word" decoding
defined by [RFC2047] and MIME parameter value decoding defined by
[RFC2231].
3. Converting downgraded message headers for display
3.1. Considerations
The order of some header fields (such as "Resent-*" fields) is
significant. The process of regenerating the original fields from
the downgraded ones MUST NOT reorder the fields.
In order to regenerate a field from a specific downgraded header
field, it's necessary to find the corresponding replacement in the
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current message. If the corresponding field can not be found, the
downgraded header field in question can not be regenerated and used.
3.2. The process
A MUA MAY decode and re-generate the original header fields of the
message (MTAs and MDAs SHOULD NOT attempt to do this; it SHOULD be
left to the MUA). This procedure can be used to approximately
reverse the Downgrade process, but it will not always construct the
original header fields exactly.
Three types of Downgraded header fields are described in section 3 of
[RFC5504]:
1. "Envelope Information Preservation Header Fields", described in
RFC5504 section 3.1 and in Section 3.2.1, below.
2. "Address Header Fields' Preservation Header Fields", described in
RFC5504 section 3.2 and in Section 3.2.2, below.
3. "Unknown Header Fields' Preservation Header Fields", described in
RFC5504 section 3.3 and in Section 3.2.3, below.
After processing Downgraded header fields, decode all header fields,
as described in [RFC2047] and [RFC2231].
3.2.1. No reconstruction of the Envelope Information Preservation
Header Fields
Envelope Information Preservation Header Fields are new fields that
might have been added by the downgrade process. Because they do not
represent fields that appeared in the original message, this process
is not applicable to them.
3.2.2. Reconstructing the Address Header Fields' Preservation Header
Fields
Reconstructing Address Header Fields' Preservation Header Fields is
OPTIONAL, and a decision MAY be made on each field, individually. In
particular, it might be less important to process the Resent-* header
fields, so an implementation MAY choose to skip those.
To construct a displayable copy of a header field from one of these
downgraded header fields, follow this procedure:
1. In an edit buffer, create a new header field:"
1a. For the field name, remove the "Downgraded-" prefix from the
downgraded field name. For example, "Downgraded-From" becomes
"From", and "Downgraded-Resent-To" becomes "Resent-To".
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1b. For the field value, decode the MIME-encoded value of the
downgraded field according to [RFC2047].
2. If the header field is one that can only appear once, according
to the table in [RFC5322] section 3.6 ("From", "Sender", "To",
"CC", "BCC", "Reply-To"), locate the corresponding field in the
message's headers, and skip to step 9. Otherwise, continue with
step 3.
3. Apply "Email Header Fields Downgrading", defined in section 5 of
[RFC5504], to the field in the edit buffer, but do not prepend the
"Downgraded-" prefix. Put the result into comparison buffer 1.
4. Canonicalize the header fields in the comparison buffer:
1. Unfold all header field continuation lines as described in
[RFC5322].
2. Ensure that there is one space character before and one after
the <mailbox-list> separator ",". If a space character is
missing, insert one.
3. Ensure that there is one space character before and one after
each <comment>. If a space character is missing, insert one.
4. Decode each <encoded-word> whose charset is "UTF-8".
5. Convert all sequences of one or more WSP characters to a
single space character. WSP characters here include those
before and after a line-folding boundary.
6. Delete all WSP characters at the end of each unfolded header
field value.
7. Delete any WSP characters remaining before and after the colon
separating the header field name from the header field value,
retaining the colon separator.
5. Locate the first instance of the corresponding field in the
message's headers.
6. Canonicalize the located field as in step 4, and put the result
into comparison buffer 2.
7. Compare the header field in comparison buffer 1 with the header
field in comparison buffer 2. If they match, go to step 9.
8. Locate the next instance of the corresponding field in the
message's headers. If one is found, go to step 6. If none is
found, stop: you can not use this downgraded field because you
can't find its replacement in the message.
9. Replace the located header field with the one in the edit
buffer. You MUST NOT reorder the header fields when you do this;
it's important to replace the field in place.
3.2.3. The Unknown Header Fields' Preservation Header Fields
The Unknown Header Fields' Preservation Header Fields SHOULD be left
as they are unless the MUA has special knowledge of a particular
field. An MUA with such knowledge MAY use the procedure in
Section 3.2.2, above, for those fields that it knows about.
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4. Security considerations
While information in any email header should usually be treated with
some suspicion, current email systems commonly employ various
mechanisms and protocols to make the information more trustworthy.
For example, an organization's boundary MTA can modify "From:" lines
so that messages arriving from outside the organization are easily
distinguishable from internal emails. As a result of that rewriting,
it might not be possible to reconstruct the "Downgraded-From" header
field.
A MUA MAY emphasize bogus or broken Address Header Fields'
Preservation Header Fields found in step 8 of Section 3.2.2.
Hiding the information from the actual header fields when using the
"Downgraded-" header fields does not cause loss of information if
generating MIME decoded header fields in step 1 of Section 3.2.2 and
the comparison done in step 8 are successful. To ensure that no
information is lost, a MUA SHOULD have a function that uses the
actual message that was received (with/without MIME decoding) to
render the message.
See "Security considerations" section in [RFC5504] and [RFC4952] for
more discussion.
5. IANA Considerations
This document makes no requests for IANA action. This section can be
removed by the RFC Editor before publication.
6. Acknowledgements
This document was separated from [RFC5504]. Both documents were
developed in the EAI WG. Significant comments and suggestions were
received from John Klensin, Harald Alvestrand, Chris Newman, Randall
Gellens, Charles Lindsey, Marcos Sanz, Alexey Melnikov, Pasi Eronen,
Frank Ellermann, Edward Lewis, S. Moonesamy and JET members.
7. Change History
This section is used for tracking the update of this document. Will
be removed after finalize.
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7.1. draft-fujiwara-eai-downgraded-display: Version 00
o Initial version
o It is separated from Appendix A of draft-ietf-eai-downgrade-05.txt
7.2. draft-ietf-eai-downgraded-display: Version 00
o Submitted as a working group draft
7.3. draft-ietf-eai-downgraded-display: Version 01
o Prohibited and removed Displaying Technique 1
o Added new texts to Security Considerations
7.4. draft-ietf-eai-downgraded-display: Version 02
o updated by comments from Chair's review and AD's review
o Fixed references
o Rewrote section 4 to be more comprehensible
o Added bogus or broken "Downgraded-" header fields
o Added sentences in Security considerations
7.5. draft-ietf-eai-downgraded-display: Version 03
o Section 3 (formerly 3 and 4) was rewritten by Barry Leiba.
8. References
8.1. Normative References
[RFC2045] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) Part One: Format of Internet Message
Bodies", RFC 2045, November 1996.
[RFC2047] Moore, K., "MIME (Multipurpose Internet Mail Extensions)
Part Three: Message Header Extensions for Non-ASCII Text",
RFC 2047, November 1996.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2183] Troost, R., Dorner, S., and K. Moore, "Communicating
Presentation Information in Internet Messages: The
Content-Disposition Header Field", RFC 2183, August 1997.
[RFC2231] Freed, N. and K. Moore, "MIME Parameter Value and Encoded
Word Extensions:
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Character Sets, Languages, and Continuations", RFC 2231,
November 1997.
[RFC4952] Klensin, J. and Y. Ko, "Overview and Framework for
Internationalized Email", RFC 4952, July 2007.
[RFC5322] Resnick, P., Ed., "Internet Message Format", RFC 5322,
October 2008.
[RFC5335] Abel, Y., "Internationalized Email Headers", RFC 5335,
September 2008.
[RFC5504] Fujiwara, K. and Y. Yoneya, "Downgrading Mechanism for
Email Address Internationalization", RFC 5504, March 2009.
8.2. Informative References
[RFC5321] Klensin, J., "Simple Mail Transfer Protocol", RFC 5321,
October 2008.
[RFC5336] Yao, J. and W. Mao, "SMTP Extension for Internationalized
Email Addresses", RFC 5336, September 2008.
[RFC5337] Newman, C. and A. Melnikov, "Internationalized Delivery
Status and Disposition Notifications", RFC 5337,
September 2008.
Appendix A. Examples
This section shows a example of displaying a downgraded message.
First, an example of the original UTF8SMTP message and its downgraded
message are shown. The example comes from "Example 1" of [RFC5504]
and three header fields, "Unknown-Field", "Resent-From", and
"Resent-To", are added. The example UTF8SMTP message is shown in
Figure 1.
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Message-Id: MESSAGE_ID
Mime-Version: 1.0
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 8bit
Subject: NON-ASCII-SUBJECT
Unknown-Field: NON-ASCII-Unknown
From: DISPLAY-local <NON-ASCII-local@example.com
<ASCII-local@example.com>>
To: DISPLAY-remote1 <NON-ASCII-remote1@example.net
<ASCII-remote1@example.net>>
Cc: DISPLAY-remote2 <NON-ASCII-remote2@example.org>
Resent-From: DISPLAY-remote1 <NON-ASCII-remote1@example.net
<ASCII-remote1@example.net>>
Resent-To: DISPLAY-reto <NON-ASCII-reto@example.net
<ASCII-reto@example.net>>
Date: DATE
MAIL_BODY
Figure 1: Original message
Delivered downgraded message is shown in Figure 2. Return-Path
header will be added by the final destination MTA. Some of Received:
header fields may be added.
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Return-Path: <ASCII-local@example.com>
Received: ...
Downgraded-Mail-From: =?UTF-8?Q?<NON-ASCII-local@example.com_?=
=?UTF-8?Q?<ASCII-local@example.com>>?=
Downgraded-Rcpt-To: =?UTF-8?Q?<NON-ASCII-remote1@example.net_?=
=?UTF-8?Q?<ASCII-remote1@example.net>>?=
Message-Id: MESSAGE_ID
Mime-Version: 1.0
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 8bit
Subject: =?UTF-8?Q?NON-ASCII-SUBJECT?=
Downgraded-Unknown-Field: =?UTF-8?Q?NON-ASCII-Unknown?=
From: =?UTF-8?Q?DISPLAY-local?= <ASCII-local@example.com>
Downgraded-From: =?UTF-8?Q?DISPLAY-local_<NON-ASCII-local@example.com_?=
=?UTF-8?Q?<ASCII-local@example.com>>?=
To: =?UTF-8?Q?DISPLAY-remote1?= <ASCII-remote1@example.net>
Downgraded-To: =?UTF-8?Q?DISPLAY-remote1_?=
=?UTF-8?Q?<NON-ASCII-remote1@example.net_<ASCII-remote1@example.net>>?=
Cc: =?UTF-8?Q?DISPLAY-remote2?= Internationalized address
=?UTF-8?Q?NON-ASCII-remote2@example.org?= removed:;
Downgraded-Cc: =?UTF-8?Q?DISPLAY-remote2_?=
=?UTF-8?Q?<NON-ASCII-remote2@example.org>?=
Resent-From: =?UTF-8?Q?DISPLAY-remote1?= <ASCII-remote1@example.net>
Downgraded-Resent-From: =?UTF-8?Q?DISPLAY-remote1_?=
=?UTF-8?Q?<NON-ASCII-remote1@example.net_<ASCII-remote1@example.net>>?=
Resent-To: =?UTF-8?Q?DISPLAY-reto?= <ASCII-reto@example.net>
Downgraded-Resent-To: =?UTF-8?Q?DISPLAY-reto_?=
=?UTF-8?Q?<NON-ASCII-reto@example.net_<ASCII-reto@example.net>>?=
Date: DATE
MAIL_BODY
Figure 2: Downgraded message
Figure 3 shows MIME decoded message of Figure 2. The recipient can
read the original From, To, Cc and Unknown-Field header fields as
Downgraded-From, Downgraded-To, Downgraded-Cc and Downgraded-Unknown-
Field header fields.
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Return-Path: <ASCII-local@example.com>
Received: ...
Downgraded-Mail-From: <NON-ASCII-local@example.com
<ASCII-local@example.com>>
Downgraded-Rcpt-To: <NON-ASCII-remote1@example.net
<ASCII-remote1@example.net>>
Message-Id: MESSAGE_ID
Mime-Version: 1.0
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 8bit
Subject: NON-ASCII-SUBJECT
Downgraded-Unknown-Field: NON-ASCII-Unknown
From: DISPLAY-local <ASCII-local@example.com>
Downgraded-From: DISPLAY-local <NON-ASCII-local@example.com
<ASCII-local@example.com>>
To: DISPLAY-remote1 <ASCII-remote1@example.net>
Downgraded-To: DISPLAY-remote1 <NON-ASCII-remote1@example.net
<ASCII-remote1@example.net>>
Cc: DISPLAY-remote2 Internationalized address
NON-ASCII-remote2@example.org removed:;
Downgraded-Cc: DISPLAY-remote2 <NON-ASCII-remote2@example.org>
Resent-From: DISPLAY-remote1 <ASCII-remote1@example.net>
Downgraded-Resent-From: DISPLAY-remote1
<NON-ASCII-remote1@example.net <ASCII-remote1@example.net>>
Resent-To: DISPLAY-reto <ASCII-reto@example.net>
Downgraded-Resent-To: DISPLAY-reto
<NON-ASCII-reto@example.net <ASCII-reto@example.net>>
Date: DATE
MAIL_BODY
Figure 3: MIME decoded message
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A.1. Displaying example
This example shows how to display the message in Figure 2, above,
using the process defined in Section 3. For simplicity, we will show
the reconstruction of all the applicable fields at once.
Selecting all Downgraded-* fields gives this:
Downgraded-Mail-From: =?UTF-8?Q?<NON-ASCII-local@example.com_?=
=?UTF-8?Q?<ASCII-local@example.com>>?=
Downgraded-Rcpt-To: =?UTF-8?Q?<NON-ASCII-remote1@example.net_?=
=?UTF-8?Q?<ASCII-remote1@example.net>>?=
Downgraded-Unknown-Field: =?UTF-8?Q?NON-ASCII-Unknown?=
Downgraded-From: =?UTF-8?Q?DISPLAY-local_<NON-ASCII-local@example.com_?=
=?UTF-8?Q?<ASCII-local@example.com>>?=
Downgraded-To: =?UTF-8?Q?DISPLAY-remote1_?=
=?UTF-8?Q?<NON-ASCII-remote1@example.net_<ASCII-remote1@example.net>>?=
Downgraded-Cc: =?UTF-8?Q?DISPLAY-remote2_?=
=?UTF-8?Q?<NON-ASCII-remote2@example.org>?=
Downgraded-Resent-From: =?UTF-8?Q?DISPLAY-remote1_?=
=?UTF-8?Q?<NON-ASCII-remote1@example.net_<ASCII-remote1@example.net>>?=
Downgraded-Resent-To: =?UTF-8?Q?DISPLAY-reto_?=
=?UTF-8?Q?<NON-ASCII-reto@example.net_<ASCII-reto@example.net>>?=
Figure 4: Downgraded header fields
Two of the fields, Downgraded-Mail-From and Downgraded-Rcpt-To, are
Envelope Information Preservation Header Fields, and will not be
reconstructed. One field, Downgraded-Unknown-Field, is an Unknown
Header Fields' Preservation Header Field, and will also not be
reconstructed. That leaves these to be reconstructed, the Address
Header Fields' Preservation Header Fields:
Downgraded-From: =?UTF-8?Q?DISPLAY-local_<NON-ASCII-local@example.com_?=
=?UTF-8?Q?<ASCII-local@example.com>>?=
Downgraded-To: =?UTF-8?Q?DISPLAY-remote1_?=
=?UTF-8?Q?<NON-ASCII-remote1@example.net_<ASCII-remote1@example.net>>?=
Downgraded-Cc: =?UTF-8?Q?DISPLAY-remote2_?=
=?UTF-8?Q?<NON-ASCII-remote2@example.org>?=
Downgraded-Resent-From: =?UTF-8?Q?DISPLAY-remote1_?=
=?UTF-8?Q?<NON-ASCII-remote1@example.net_<ASCII-remote1@example.net>>?=
Downgraded-Resent-To: =?UTF-8?Q?DISPLAY-reto_?=
=?UTF-8?Q?<NON-ASCII-reto@example.net_<ASCII-reto@example.net>>?=
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Figure 5: Header fields for the reconstruction
Now, perform Step 1, creating temporary fields.
From: DISPLAY-local <NON-ASCII-local@example.com
<ASCII-local@example.com>>
To: DISPLAY-remote1 <NON-ASCII-remote1@example.net
<ASCII-remote1@example.net>>
Cc: DISPLAY-remote2 <NON-ASCII-remote2@example.org>
Resent-From: DISPLAY-remote1
<NON-ASCII-remote1@example.net <ASCII-remote1@example.net>>
Resent-To: DISPLAY-reto
<NON-ASCII-reto@example.net <ASCII-reto@example.net>>
Figure 6: Output of Step 1
In step 2, we set aside the "From", "To", and "Cc" fields, and
continue to step 3 with just "Resent-From" and "Resent-To" (the
fields that may appear more than once). The fields we set aside will
be picked up again later, in step 9.
Perform Steps 3 and 4. The edit buffer contains re-generated ASCII
header fields, canonicalized.
Resent-From: =?UTF-8?Q?DISPLAY-remote1?= <ASCII-remote1@example.net>
Resent-To: =?UTF-8?Q?DISPLAY-reto?= <ASCII-reto@example.net>
Figure 7: The edit buffer (output of Step 4)
Perform Steps 5 to 7, comparison, for each header field. Both the
Resent-From and Resent-To fields will match, and we will proceed to
step 9. (Step 8, iteration, does not apply in this example.
Perform step 9, replacing all applicable fields, without changing the
order. Then do MIME decoding on everything, for display.
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Return-Path: <ASCII-local@example.com>
Received: ...
Downgraded-Mail-From: <NON-ASCII-local@example.com
<ASCII-local@example.com>>
Downgraded-Rcpt-To: <NON-ASCII-remote1@example.net>
<ASCII-remote1@example.net>
Message-Id: MESSAGE_ID
Mime-Version: 1.0
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 8bit
Subject: NON-ASCII-SUBJECT
Downgraded-Unknown-Field: NON-ASCII-Unknown
From: DISPLAY-local <NON-ASCII-local@example.com
<ASCII-local@example.com>>
To: DISPLAY-remote1 <NON-ASCII-remote1@example.net
<ASCII-remote1@example.net>>
Cc: DISPLAY-remote2 <NON-ASCII-remote2@example.org>
Resent-From: DISPLAY-remote1 <NON-ASCII-remote1@example.net
<ASCII-remote1@example.net>>
Resent-To: DISPLAY-reto <NON-ASCII-reto@example.net
<ASCII-reto@example.net>>
Date: DATE
Figure 8: The final result
As a result, in this simple example, some original header fields are
now displayed in their original form. Differences between Figure 1
and Figure 8 are Return-Path, Downgraded-Mail-From,
Downgraded-Rcpt-To, and Downgraded-Unknown-Field.
Authors' Addresses
Kazunori Fujiwara
Japan Registry Services Co., Ltd.
Chiyoda First Bldg. East 13F, 3-8-1 Nishi-Kanda
Chiyoda-ku, Tokyo 101-0065
Japan
Phone: +81-3-5215-8451
Email: fujiwara@jprs.co.jp
Fujiwara & Leiba Expires June 4, 2010 [Page 14]
Internet-Draft Displaying Downgraded Messages December 2009
Barry Leiba
Huawei Technologies
Phone: +1 646 827 0648
Email: barryleiba@computer.org
URI: http://internetmessagingtechnology.org/
Fujiwara & Leiba Expires June 4, 2010 [Page 15]