Email Address Internationalization K. Fujiwara
(EAI) JPRS
Internet-Draft July 11, 2011
Intended status: Standards Track
Expires: January 12, 2012
Post-delivery Message Downgrading for Internationalized Email Messages
draft-ietf-eai-popimap-downgrade-02.txt
Abstract
The Email Address Internationalization (UTF8SMTP) extension allows
UTF-8 characters in mail header fields. POP and IMAP servers support
internationalized email messages. If a POP/IMAP client does not
support Email Address Internationalization, POP/IMAP servers cannot
send Internationalized Email Headers to the client and cannot remove
the message. To avoid the situation, this document describes a
conversion mechanism for internationalized Email messages to be
traditional message format.
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
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This Internet-Draft will expire on January 12, 2012.
Copyright Notice
Copyright (c) 2011 IETF Trust and the persons identified as the
document authors. All rights reserved.
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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
carefully, as they describe your rights and restrictions with respect
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the Trust Legal Provisions and are provided without warranty as
described in the BSD License.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Updating RFC 5322 . . . . . . . . . . . . . . . . . . . . . . 4
4. New Header Fields Definition . . . . . . . . . . . . . . . . . 5
4.1. Unknown Header Fields' Preservation Header Fields . . . . 5
5. Email Header Fields Downgrading . . . . . . . . . . . . . . . 6
5.1. Downgrading Method for Each ABNF Element . . . . . . . . . 6
5.1.1. RECEIVED Downgrading . . . . . . . . . . . . . . . . . 7
5.1.2. UNSTRUCTURED Downgrading . . . . . . . . . . . . . . . 7
5.1.3. WORD Downgrading . . . . . . . . . . . . . . . . . . . 7
5.1.4. COMMENT Downgrading . . . . . . . . . . . . . . . . . 7
5.1.5. MIME-VALUE Downgrading . . . . . . . . . . . . . . . . 7
5.1.6. DISPLAY-NAME Downgrading . . . . . . . . . . . . . . . 7
5.1.7. GROUP Downgrading . . . . . . . . . . . . . . . . . . 7
5.1.8. MAILBOX Downgrading . . . . . . . . . . . . . . . . . 8
5.1.9. ENCAPSULATION Downgrading . . . . . . . . . . . . . . 8
5.1.10. TYPED-ADDRESS Downgrading . . . . . . . . . . . . . . 8
5.2. Downgrading Method for Each Header Field . . . . . . . . . 8
5.2.1. Address Header Fields That Contain <address>s . . . . 9
5.2.2. Address Header Fields with Typed Addresses . . . . . . 9
5.2.3. Downgrading Non-ASCII in Comments . . . . . . . . . . 9
5.2.4. Received Header Field . . . . . . . . . . . . . . . . 10
5.2.5. MIME Content Header Fields . . . . . . . . . . . . . . 10
5.2.6. Non-ASCII in <unstructured> . . . . . . . . . . . . . 10
5.2.7. Non-ASCII in <phrase> . . . . . . . . . . . . . . . . 10
5.2.8. Other Header Fields . . . . . . . . . . . . . . . . . 10
6. MIME Body-Part Header Field Downgrading . . . . . . . . . . . 11
7. Security Considerations . . . . . . . . . . . . . . . . . . . 11
8. Implementation Notes . . . . . . . . . . . . . . . . . . . . . 12
8.1. RFC 2047 Encoding . . . . . . . . . . . . . . . . . . . . 12
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 13
11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13
11.1. Normative References . . . . . . . . . . . . . . . . . . . 13
11.2. Informative References . . . . . . . . . . . . . . . . . . 14
Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 14
A.1. Downgrading Example . . . . . . . . . . . . . . . . . . . 14
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1. Introduction
Traditional mail systems, which are defined by [RFC5322], allow ASCII
characters in mail header field values. The UTF8SMTP extension
([I-D.ietf-eai-frmwrk-4952bis] and [I-D.ietf-eai-rfc5335bis] allows
UTF-8 characters in mail header field values.
If a header field contains non-ASCII characters, POP/IMAP servers
cannot send Internationalized Email Headers to the client and cannot
remove the message. This message downgrading mechanism converts mail
header fields to an all-ASCII representation. The POP/IMAP servers
can use the downgrading mechanism and send the Internationalized
Email message as a traditional form.
[I-D.ietf-eai-rfc5335bis] allows UTF-8 characters to be used in mail
header fields and MIME header fields. The message downgrading
mechanism specified here describes the conversion method from the
internationalized email messages that are defined in
[I-D.ietf-eai-frmwrk-4952bis], and [I-D.ietf-eai-rfc5335bis] to the
traditional email messages defined in [RFC5322].
There is no good way to convert "From:" and "Sender:" header fields,
the draft need to update [RFC5322] to allow empty "From:" and
"Sender:" header fields and it is described in Section 3.
Message Downgrading may be implemented in POP server and IMAP server
only.
This document tries to define the message downgrading process
clearly.
Downgrading consists of the following four parts:
o Updating RFC 5322
o New header field definitions
o Email header field downgrading
o MIME header field downgrading
In Section 4 of this document, header fields starting with
"Downgraded-" are introduced. They preserve the original header
fields.
Email header field downgrading is described in Section 5. It
generates ASCII-only header fields.
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MIME header fields are expanded in [I-D.ietf-eai-rfc5335bis]. MIME
header field downgrading is described in Section 6. It generates
ASCII-only MIME header fields.
Displaying downgraded messages that originally contained
internationalized header fields is out of scope of this document. A
POP/IMAP client which does not support UTF8 extension does not know
internationalized message format described in
[I-D.ietf-eai-rfc5335bis].
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].
All specialized terms used in this specification are defined in the
Email Address Internationalization (EAI) overview
[I-D.ietf-eai-frmwrk-4952bis], in the mail message specifications
[RFC5322], or in the MIME documents [RFC2045] [RFC2047] [RFC2183]
[RFC2231]. The terms "ASCII address", "internationalized email
address", "non-ASCII address", "i18mail address", "UTF8SMTP",
"message", and "mailing list" are used with the definitions from
[I-D.ietf-eai-frmwrk-4952bis].
This document depends on [I-D.ietf-eai-rfc5335bis]. Key words used
in those documents are used in this document, too.
The term "non-ASCII" refers to a UTF-8 string that contains at least
one non-ASCII character.
A "UTF8SMTP message" is an email message expanded by
[I-D.ietf-eai-rfc5335bis].
3. Updating RFC 5322
"From:" header field or "Sender:" header field may contain non-ASCII
addresses in internationalized Email messages. These non-ASCII
addresses are not allowed in [RFC5322]. The draft proposes that the
pop/imap downgrading uses <group> syntax and encodes non-ASCII
addresses into <display-name> with empty <group-list> described in
Section 5.
This specification redefines "From:", "Sender:", "Resent-From:" and
"Resent-Sender:" header fields defined in Section 3.6.2 and 3.6.6 of
[RFC5322] to allow <group> in the header fields.
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from = "From:" address-list CRLF
resent-from = "Resent-From:" address-list CRLF
sender = "Sender:" address CRLF
resent-sender = "Resent-Sender:" address CRLF
[[Note in Draft: There are still outstanding questions about the use
of group syntax that the WG should resolve, or confirm that it is
willing to live with and figure out how to describe in the document,
at IETF 81. They include
1. RFC 5322 does not allow group syntax in From and Sender header
fields. Existing MUAs may become very confused when they see
group syntax in originator fields.
2. Use of group syntax in this way will essentially make it
impossible to reply to a message.
3. "Reply-To:" header field allows the group syntax in [RFC5322].
Is it correct ?
4. The ABNF syntax here is not yet complete.
5. Should the document explicitly recommend the use of comments,
possibly with encoded words, to document the original non-ASCII
mailboxes?
Suggestion made to the WG for more in depth discussion. ]]
4. New Header Fields Definition
New header fields starting with "Downgraded-" are defined here to
preserve those mail header field values that contain UTF-8
characters. During downgrading, one new "Downgraded-" header field
is added for each mail header field that cannot be passed as-is to a
POP/IMAP client that does not support UTF8 extension. The original
mail header field is removed or rewritten. Only those mail header
fields that contain non-ASCII characters are affected. The result of
this process is a message that is compliant with existing email
specifications [RFC5322]. The original internationalized information
can be retrieved by examining the "Downgraded-" header fields that
were added.
4.1. Unknown Header Fields' Preservation Header Fields
The unknown header fields' preservation header fields are defined to
encapsulate those original header fields that contain non-ASCII
characters and are not otherwise provided for in this specification.
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The encapsulation header field name is the concatenation of
"Downgraded-" and the original name. The value field holds the
original header field value.
The header field syntax is specified as follows:
fields =/ unknown-downgraded-headers ":" unstructured CRLF
unknown-downgraded-headers = "Downgraded-" original-header-field-name
original-header-field-name = field-name
field-name = 1*ftext
ftext = %d33-57 / ; Any character except
%d59-126 ; controls, SP, and ":".
To encapsulate a header field in a "Downgraded-" header field:
1. Generate a new "Downgraded-" header field whose value is the
original header field value.
2. Treat the generated header field content as if it were
unstructured, and then apply [RFC2047] encoding with charset
UTF-8 as necessary so the result is ASCII.
3. Remove the original header field.
5. Email Header Fields Downgrading
This section defines the conversion method to ASCII for each header
field that may contain non-ASCII characters.
[I-D.ietf-eai-rfc5335bis] expands "Received:" header fields;
[RFC5322] describes ABNF elements <mailbox>, <word>, <comment>,
<unstructured>; [RFC2045] describes ABNF element <value>.
5.1. Downgrading Method for Each ABNF Element
Header field downgrading is defined below for each ABNF element.
Downgrading an unknown header field is also defined as ENCAPSULATION
downgrading. Converting the header field terminates when no non-
ASCII characters remain in the header field.
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5.1.1. RECEIVED Downgrading
If the header field name is "Received:" and the FOR clause contains a
non-ASCII address, remove the FOR clause from the header field.
Other parts (not counting <comment>s) should not contain non-ASCII
values.
5.1.2. UNSTRUCTURED Downgrading
If the header field has an <unstructured> field that contains non-
ASCII characters, apply [RFC2047] encoding with charset UTF-8.
5.1.3. WORD Downgrading
If the header field has any <word> fields that contain non-ASCII
characters, apply [RFC2047] encoding with charset UTF-8.
5.1.4. COMMENT Downgrading
If the header field has any <comment> fields that contain non-ASCII
characters, apply [RFC2047] encoding with charset UTF-8.
5.1.5. MIME-VALUE Downgrading
If the header field has any <value> elements defined by [RFC2045] and
the elements contain non-ASCII characters, encode the <value>
elements according to [RFC2231] with charset UTF-8 and leave the
language information empty. If the <value> element is <quoted-
string> and it contains <CFWS> outside the DQUOTE, remove the <CFWS>
before this conversion.
5.1.6. DISPLAY-NAME Downgrading
If the header field has any <address> (<mailbox> or <group>) elements
and they have <display-name> elements that contain non-ASCII
characters, encode the <display-name> elements according to [RFC2047]
with charset UTF-8. DISPLAY-NAME downgrading is the same algorithm
as WORD downgrading.
5.1.7. GROUP Downgrading
<group> is defined in Section 3.4 of [RFC5322]. The <group> elements
may contain <mailbox>s which contain non-ASCII addresses.
If the header field has any <group> elements which contain <mailbox>
elements that contain non-ASCII addresses, rewrite each <group>
element as
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"Internationalized_Address_Removed" display-name ENCODED_WORD ":;" [CFWS]
where the <ENCODED_WORD> is the original <group-list> encoded
according to [RFC2047].
5.1.8. MAILBOX Downgrading
The <mailbox> elements have no equivalent format for non-ASCII
addresses. If the header field has any <mailbox> elements that
contain non-ASCII characters, rewrite each <mailbox> element to
ASCII-only format. The <mailbox> element that contains non-ASCII
characters is one of two formats.
[ Display-name ] "<" Utf8-addr-spec ">"
Utf8-addr-spec
Rewrite both as:
[ Display-name ] "Internationalized Address " Encoded-word
" Removed:;"
where the <Encoded-word> is the original <Utf8-addr-spec> encoded
according to [RFC2047].
5.1.9. ENCAPSULATION Downgrading
If the header field contains non-ASCII characters and is such that no
rule is given above, encapsulate it in a "Downgraded-" header field
as described in Section 4.1 as a last resort.
Applying this procedure to "Received:" header field is prohibited.
5.1.10. TYPED-ADDRESS Downgrading
If the header field contains <utf-8-type-addr> and the <utf-8-type-
addr> contains raw non-ASCII characters, it is in utf-8-address form.
Convert it to utf-8-addr-xtext form. Those forms are described in
[I-D.ietf-eai-rfc5337bis-dsn]. COMMENT downgrading is also performed
in this case. If the address type is unrecognized and the header
field contains non-ASCII characters, then fall back to using
ENCAPSULATION downgrading on the entire header field.
5.2. Downgrading Method for Each Header Field
Header fields are listed in [RFC4021]. This section describes the
downgrading method for each header field.
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If the whole mail header field does not contain non-ASCII characters,
email header field downgrading is not required. Each header field's
downgrading method is described below.
5.2.1. Address Header Fields That Contain <address>s
From:
Sender:
To:
Cc:
Bcc:
Reply-To:
Resent-From:
Resent-Sender:
Resent-To:
Resent-Cc:
Resent-Bcc:
Resent-Reply-To:
Return-Path:
Disposition-Notification-To:
If the header field contains <group> elements that contain non-ASCII
addresses, perform COMMENT downgrading, DISPLAY-NAME downgrading, and
GROUP downgrading.
If the header field contains <mailbox> elements that contain non-
ASCII addresses, perform COMMENT downgrading, DISPLAY-NAME
downgrading, and MAILBOX downgrading.
5.2.2. Address Header Fields with Typed Addresses
Original-Recipient:
Final-Recipient:
If the header field contains non-ASCII characters, perform TYPED-
ADDRESS downgrading.
5.2.3. Downgrading Non-ASCII in Comments
Date:
Message-ID:
Resent-Message-ID:
In-Reply-To:
References:
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Resent-Date:
Resent-Message-ID:
MIME-Version:
Content-ID:
Content-Transfer-Encoding:
Content-Language:
Accept-Language:
Auto-Submitted:
These header fields do not contain non-ASCII characters except in
comments. If the header field contains UTF-8 characters in comments,
perform COMMENT downgrading.
5.2.4. Received Header Field
Received:
Perform COMMENT downgrading and RECEIVED downgrading.
5.2.5. MIME Content Header Fields
Content-Type:
Content-Disposition:
Perform MIME-VALUE downgrading and COMMENT downgrading.
5.2.6. Non-ASCII in <unstructured>
Subject:
Comments:
Content-Description:
Perform UNSTRUCTURED downgrading.
5.2.7. Non-ASCII in <phrase>
Keywords:
Perform WORD downgrading.
5.2.8. Other Header Fields
For all other header fields that contain non-ASCII characters, are
user-defined, and are missing from this document or future defined
header fields, perform ENCAPSULATION downgrading.
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If the software understands the header field's structure and a
downgrading algorithm other than ENCAPSULATION is applicable, that
software SHOULD use that algorithm; ENCAPSULATION downgrading is used
as a last resort.
Mailing list header fields (those that start in "List-") are part of
this category.
6. MIME Body-Part Header Field Downgrading
MIME body-part header fields may contain non-ASCII characters
[I-D.ietf-eai-rfc5335bis]. This section defines the conversion
method to ASCII-only header fields for each MIME header field that
contains non-ASCII characters. Parse the message body's MIME
structure at all levels and check each MIME header field to see
whether it contains non-ASCII characters. If the header field
contains non-ASCII characters in the header field value, the header
field is a target of the MIME body-part header field's downgrading.
Each MIME header field's downgrading method is described below.
COMMENT downgrading, MIME-VALUE downgrading, and UNSTRUCTURED
downgrading are described in Section 5.
Content-ID:
The "Content-ID:" header field does not contain non-ASCII
characters except in comments. If the header field contains UTF-8
characters in comments, perform COMMENT downgrading.
Content-Type:
Content-Disposition: Perform MIME-VALUE downgrading and COMMENT
downgrading.
Content-Description: Perform UNSTRUCTURED downgrading.
7. Security Considerations
A downgraded message's header fields contain ASCII characters only.
But they still contain MIME-encapsulated header fields that contain
non-ASCII UTF-8 characters. Furthermore, the body part may contain
UTF-8 characters. Implementations parsing Internet messages need to
accept UTF-8 body parts and UTF-8 header fields that are MIME-
encoded. Thus, this document inherits the security considerations of
MIME-encoded header fields ([RFC2047] and [RFC3629]).
Rewriting header fields increases the opportunities for undetected
spoofing by malicious senders. However, rewritten header fields are
preserved into Downgraded-* header fields, and parsing Downgraded-*
header fields enables the detection of spoofing caused by
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downgrading.
The techniques described here invalidate methods that depend on
digital signatures over any part of the message, which includes the
top-level header fields and body-part header fields. Depending on
the specific message being downgraded, the following techniques are
likely to break: DomainKeys Identified Mail (DKIM), and possibly
S/MIME and Pretty Good Privacy (PGP). The two obvious mitigations
are to stick to 7-bit transport when using these techniques (as most/
all of them presently require) or to make sure to have UTF8SMTP end-
to-end when needed.
While information in any email header field should usually be treated
with some suspicion, current email systems commonly employ various
mechanisms and protocols to make the information more trustworthy.
Currently, information in the new Downgraded-* header fields is
usually not inspected by these mechanisms, and may be even less
trustworthy than the traditional header fields. Note that the
Downgraded-* header fields could have been inserted with malicious
intent (and with content unrelated to the traditional header fields).
See the "Security Considerations" section in
[I-D.ietf-eai-frmwrk-4952bis] for more discussion.
8. Implementation Notes
8.1. RFC 2047 Encoding
While [RFC2047] has a specific algorithm to deal with whitespace in
adjacent encoded words, there are a number of deployed
implementations that fail to implement the algorithm correctly. As a
result, whitespace behavior is somewhat unpredictable in practice
when multiple encoded words are used. While RFC 5322 states that
implementations SHOULD limit lines to not more than 78 characters,
implementations MAY choose to allow overly long encoded words in
order to work around faulty [RFC2047] implementations.
Implementations that choose to do so SHOULD have an optional
mechanism to limit line length to 78 characters.
9. IANA Considerations
IANA is requested to refuse registration of all field names that
start with "Downgraded-". For unknown header fields, use the
downgrading method described in Section 4.1 to avoid conflicts with
existing IETF activity (Email Address Internationalization).
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10. Acknowledgements
This document draws heavily from the experimental in-transit message
downgrading procedure described in RFC 5504 [RFC5504]. The
contribution of the co-author of that earlier document, Y. Yoneya,
are gratefully acknowledged.
11. References
11.1. Normative References
[I-D.ietf-eai-frmwrk-4952bis] Klensin, J. and Y. Ko, "Overview and
Framework for Internationalized
Email",
draft-ietf-eai-frmwrk-4952bis-10 (work
in progress), September 2010.
[I-D.ietf-eai-rfc5335bis] Yang, A., Steele, S., and N. Freed,
"Internationalized Email Headers",
draft-ietf-eai-rfc5335bis-11 (work in
progress), July 2011.
[I-D.ietf-eai-rfc5337bis-dsn] Hansen, T., Newman, C., and A.
Melnikov, "Internationalized Delivery
Status and Disposition Notifications",
draft-ietf-eai-rfc5337bis-dsn-02 (work
in progress), April 2011.
[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.
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[RFC2231] Freed, N. and K. Moore, "MIME
Parameter Value and Encoded Word
Extensions: Character Sets, Languages,
and Continuations", RFC 2231,
November 1997.
[RFC3629] Yergeau, F., "UTF-8, a transformation
format of ISO 10646", STD 63,
RFC 3629, November 2003.
[RFC4021] Klyne, G. and J. Palme, "Registration
of Mail and MIME Header Fields",
RFC 4021, March 2005.
[RFC5322] Resnick, P., Ed., "Internet Message
Format", RFC 5322, October 2008.
11.2. Informative References
[RFC5504] Fujiwara, K. and Y. Yoneya,
"Downgrading Mechanism for Email
Address Internationalization",
RFC 5504, March 2009.
Appendix A. Examples
A.1. Downgrading Example
This appendix shows an message downgrading example. Consider a
received mail message where:
o The sender address is a non-ASCII address,
"NON-ASCII-local@example.com". Its display-name is "DISPLAY-
local".
o The "To:" header field contains two non-ASCII addresses,
"NON-ASCII-remote1@example.net" and
"NON-ASCII-remote2@example.com" Its display-names are "DISPLAY-
remote1" and "DISPLAY-remote2".
o The "Cc:" header field contains a non-ASCII address,
"NON-ASCII-remote3@example.org". Its display-name is "DISPLAY-
remote3".
o Four display names contain non-ASCII characters.
o The Subject header field is "NON-ASCII-SUBJECT", which contains
non-ASCII characters.
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o There is an unknown header field "X-Unknown-Header" which contains
non-ASCII characters.
Return-Path: <NON-ASCII-local@example.com>
Received: from ... by ... for <NON-ASCII-remote1@example.net>
Received: from ... by ... for <NON-ASCII-remote1@example.net>
From: DISPLAY-local <NON-ASCII-local@example.com>
To: DISPLAY-remote1 <NON-ASCII-remote1@example.net>,
DISPLAY-remote2 <NON-ASCII-remote2@example.com>
Cc: DISPLAY-remote3 <NON-ASCII-remote3@example.org>
Subject: NON-ASCII-SUBJECT
Date: DATE
Message-Id: MESSAGE_ID
Mime-Version: 1.0
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 8bit
X-Unknown-Header: NON-ASCII-CHARACTERS
MAIL_BODY
Figure 1: Received message in a mail drop
The downgraded message is shown in Figure 2. "Return-Path:",
"From:", "To:" and "Cc:" header fields are rewritten. "X-Unknown-
Header:" is encapsulated as "Downgraded-X-Unknown-Header:".
Fujiwara Expires January 12, 2012 [Page 16]
Internet-Draft POP/IMAP Downgrade July 2011
Return-Path: Internationalized address
=?UTF-8?Q?NON-ASCII-local@example.com?= removed:;
Received: from ... by ...
Received: from ... by ...
From: =?UTF-8?Q?DISPLAY-local?= Internationalized address
=?UTF-8?Q?NON-ASCII-local@example.com?= removed:;
To: =?UTF-8?Q?DISPLAY-remote1?= Internationalized address
=?UTF-8?Q?NON-ASCII-remote1@example.net?= removed:;,
=?UTF-8?Q?DISPLAY-remote2?= Internationalized address
=?UTF-8?Q?NON-ASCII-remote2@example.com?= removed:;,
Cc: =?UTF-8?Q?DISPLAY-remote3?= Internationalized address
=?UTF-8?Q?NON-ASCII-remote3@example.org?= removed:;
Subject: =?UTF-8?Q?NON-ASCII-SUBJECT?=
Date: DATE
Message-Id: MESSAGE_ID
Mime-Version: 1.0
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 8bit
Downgraded-X-Unknown-Header: =?UTF-8?Q?NON-ASCII-CHARACTERS?=
MAIL_BODY
Figure 2: Downgraded message
Author's Address
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 Expires January 12, 2012 [Page 17]
