Internet Engineering Task Force (IETF) M. Kucherawy, Ed.
Request for Comments: 6522 Cloudmark
STD: 73 January 2012
Obsoletes: 3462
Category: Standards Track
ISSN: 2070-1721
The Multipart/Report Media Type for
the Reporting of Mail System Administrative Messages
Abstract
The multipart/report Multipurpose Internet Mail Extensions (MIME)
media type is a general "family" or "container" type for electronic
mail reports of any kind. Although this memo defines only the use of
the multipart/report media type with respect to delivery status
reports, mail processing programs will benefit if a single media type
is used for all kinds of reports.
This memo obsoletes "The Multipart/Report Content Type for the
Reporting of Mail System Administrative Messages", RFC 3462, and
marks RFC 3462 and its predecessor as "Historic".
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc6522.
Kucherawy Standards Track [Page 1]
RFC 6522 Multipart/Report Media Type January 2012
Copyright Notice
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document authors. All rights reserved.
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than English.
Table of Contents
1. Introduction ....................................................3
2. Document Conventions ............................................3
3. The Multipart/Report Media Type .................................3
4. The text/rfc822-headers Media Type ..............................5
5. Registering New Report Types ....................................7
6. IANA Considerations .............................................7
7. Security Considerations .........................................7
8. References ......................................................7
8.1. Normative References .......................................7
8.2. Informative References .....................................8
Appendix A. Acknowledgements ......................................9
Kucherawy Standards Track [Page 2]
RFC 6522 Multipart/Report Media Type January 2012
1. Introduction
[OLD-REPORT] and its antecedent declared the multipart/report media
type for use within the [MIME] construct to create a container for
mail system administrative reports of various kinds.
Practical experience has shown that the general requirement of having
that media type constrained to be used only as the outermost MIME
type of a message is overly restrictive and limits such things as the
transmission of multiple administrative reports within a single
overall message container. In particular, it prevents one from
forwarding a report as part of another multipart MIME message.
This memo removes that constraint. No other changes apart from some
editorial ones are made. Other memos might update other documents to
establish or clarify the constraints on use of multipart/report in
contexts where such are needed.
This memo obsoletes RFC 3462. RFC 3462 and its predecessor, RFC
1892, have been marked as "Historic".
2. Document Conventions
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 [KEYWORDS].
3. The Multipart/Report Media Type
The multipart/report MIME media type is a general "family" or
"container" type for electronic mail reports of any kind. Although
this memo defines only the use of the multipart/report media type
with respect to delivery status reports, mail processing programs
will benefit if a single media type is used for all kinds of reports.
Per [MIME-REG], the multipart/report media type is defined as
follows:
Type name: multipart
Subtype name: report
Required parameters: boundary, report-type
Optional parameters: none
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RFC 6522 Multipart/Report Media Type January 2012
Encoding considerations: 7bit should always be adequate
Security considerations: see Section 7 of [RFC6522]
Interoperability considerations: see Section 1 of [RFC6522]
Published specification: [RFC6522]
Applications that use this media type: Mail Transfer Agents, Mail
User Agents, spam detection and reporting modules, virus detection
modules, and message authentication modules.
Additional information:
Magic number(s): N/A
File extension(s): N/A
Macintosh file type code(s): N/A
Person and email address to contact for further information: Murray
S. Kucherawy <msk@cloudmark.com>
Intended usage: common
Restrictions on usage: none; however, other applications that
register report types may establish such restrictions.
Author: Murray S. Kucherawy <msk@cloudmark.com>
Change controller: IESG
The syntax of multipart/report is identical to the multipart/mixed
content type defined in [MIME]. The report-type parameter identifies
the type of report. The parameter is the MIME subtype of the second
body part of the multipart/report. (See Section 5.)
The multipart/report media type contains either two or three sub-
parts, in the following order:
1. (REQUIRED) The first body part contains a human-readable message.
The purpose of this message is to provide an easily understood
description of the condition(s) that caused the report to be
generated, for a human reader who might not have a user agent
capable of interpreting the second section of the multipart/
report. The text in the first section can use any IANA-
registered MIME media type, charset, or language. Where a
description of the error is desired in several languages or
Kucherawy Standards Track [Page 4]
RFC 6522 Multipart/Report Media Type January 2012
several media, a multipart/alternative construct MAY be used.
This body part MAY also be used to send detailed information that
cannot be easily formatted into the second body part.
2. (REQUIRED) A machine-parsable body part containing an account of
the reported message handling event. The purpose of this body
part is to provide a machine-readable description of the
condition(s) that caused the report to be generated, along with
details not present in the first body part that might be useful
to human experts. An initial body part, message/delivery-status,
is defined in [DSN-FORMAT].
3. (OPTIONAL) A body part containing the returned message or a
portion thereof. This information could be useful to aid human
experts in diagnosing problems. (Although it might also be
useful to allow the sender to identify the message about which
the report was issued, it is hoped that the envelope-id and
original-recipient-address returned in the message/report body
part will replace the traditional use of the returned content for
this purpose.)
Return of content can be wasteful of network bandwidth and a variety
of implementation strategies can be used. Generally, the sender
needs to choose the appropriate strategy and inform the recipient of
the required level of returned content required. In the absence of
an explicit request for level of return of content such as that
provided in [DSN-SMTP], the agent that generated the delivery service
report SHOULD return the full message content.
When 8-bit or binary data not encoded in a 7-bit form is to be
returned, and the return path is not guaranteed to be 8-bit or binary
capable, two options are available. The original message MAY be
re-encoded into a legal 7-bit MIME message or the text/rfc822-headers
media type MAY be used to return only the original message headers.
4. The text/rfc822-headers Media Type
The text/rfc822-headers media type provides a mechanism to label and
return only the [MAIL] header of a failed message. The header is not
the complete message and SHOULD NOT be returned using the message/
rfc822 media type defined in [MIME-TYPES]. The returned header is
useful for identifying the failed message and for diagnostics based
on the Received header fields.
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RFC 6522 Multipart/Report Media Type January 2012
The text/rfc822-headers media type is defined as follows:
Type name: text
Subtype name: rfc822-headers
Required parameters: None
Optional parameters: None
Encoding considerations: 7-bit is sufficient for normal mail
headers, however, if the headers are broken or extended and
require encoding to make them legal 7-bit content, they MAY be
encoded with quoted-printable as defined in [MIME].
Security considerations: See Section 7 of [RFC6522].
Interoperability considerations: none
Published specification: [RFC6522]
Applications that use this media type: Mail Transfer Agents, Mail
User Agents, spam detection and reporting modules, virus detection
modules, and message authentication modules.
Additional information:
Magic number(s): N/A
File extension(s): N/A
Macintosh file type code(s): N/A
Person and email address to contact for further information: Murray
S. Kucherawy <msk@cloudmark.com>
Intended usage: common
Restrictions on usage: none
Author: Murray S. Kucherawy <msk@cloudmark.com>
Change controller: IESG
The text/rfc822-headers body part SHOULD contain all the mail header
fields from the message that caused the report. The header includes
all header fields prior to the first blank line in the message. They
include the MIME-Version and MIME content description fields.
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RFC 6522 Multipart/Report Media Type January 2012
5. Registering New Report Types
Registration of new media types for the purpose of creating a new
report format SHOULD note in the Intended Usage section of the media
type registration that the type being registered is suitable for use
as a report-type (i.e., the second body part) in the context of this
specification.
6. IANA Considerations
IANA has updated the Media Type Registry to indicate that this memo
contains the current definition of the multipart/report and text/
rfc822-headers media types, obsoleting [OLD-REPORT].
7. Security Considerations
Automated use of report types without authentication presents several
security issues. Forging negative reports presents the opportunity
for denial-of-service attacks when the reports are used for automated
maintenance of directories or mailing lists. Forging positive
reports can cause the sender to incorrectly believe a message was
delivered when it was not.
A signature covering the entire multipart/report structure could be
used to prevent such forgeries; such a signature scheme is, however,
beyond the scope of this document.
8. References
8.1. Normative References
[KEYWORDS] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[MAIL] Resnick, P., Ed., "Internet Message Format", RFC 5322,
October 2008.
[MIME] Freed, N. and N. Borenstein, "Multipurpose Internet
Mail Extensions (MIME) Part One: Format of Internet
Message Bodies", RFC 2045, November 1996.
[MIME-REG] Freed, N. and J. Klensin, "Media Type Specifications
and Registration Procedures", BCP 13, RFC 4288,
December 2005.
[MIME-TYPES] Freed, N. and N. Borenstein, "Multipurpose Internet
Mail Extensions (MIME) Part Two: Media Types",
RFC 2046, November 1996.
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RFC 6522 Multipart/Report Media Type January 2012
8.2. Informative References
[DSN-FORMAT] Moore, K. and G. Vaudreuil, "An Extensible Message
Format for Delivery Status Notifications", RFC 3464,
January 2003.
[DSN-SMTP] Moore, K., "Simple Mail Transfer Protocol (SMTP)
Service Extension for Delivery Status Notifications
(DSNs)", RFC 3461, January 2003.
[OLD-REPORT] Vaudreuil, G., "The Multipart/Report Content Type for
the Reporting of Mail System Administrative Messages",
RFC 3462, January 2003.
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RFC 6522 Multipart/Report Media Type January 2012
Appendix A. Acknowledgements
The author would like to thank Dave Crocker, Frank Ellermann, Ned
Freed, Randall Gellens, Alexey Melnikov, and Keith Moore for their
input to this update.
Thanks also go to Gregory M. Vaudreuil, the original creator of this
media type.
Author's Address
Murray S. Kucherawy (editor)
Cloudmark
128 King St., 2nd Floor
San Francisco, CA 94107
US
Phone: +1 415 946 3800
EMail: msk@cloudmark.com
Kucherawy Standards Track [Page 9]