Individual Submission M. Kucherawy
Internet-Draft Cloudmark
Obsoletes: 3462 (if approved) August 29, 2011
Intended status: Standards Track
Expires: March 1, 2012
The Multipart/Report Media Type for the Reporting of Mail System
Administrative Messages
draft-ietf-appsawg-rfc3462bis-00
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 RFC3462.
Status of this Memo
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Document Conventions . . . . . . . . . . . . . . . . . . . . . 4
3. The multipart/report Media Type . . . . . . . . . . . . . . . 5
4. The text/rfc822-headers Media Type . . . . . . . . . . . . . . 7
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
6. Security Considerations . . . . . . . . . . . . . . . . . . . 9
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 10
7.1. Normative References . . . . . . . . . . . . . . . . . . . 10
7.2. Informative References . . . . . . . . . . . . . . . . . . 10
Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 11
Appendix B. Document History . . . . . . . . . . . . . . . . . . 12
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 13
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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, while well-intentioned, has provided little
operational benefit and actually 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 mulipart 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 constraint where it is more appropriate.
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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 BCP 14, [KEYWORDS].
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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:
MIME type name: multipart
MIME subtype name: report
Required parameters: boundary, report-type
Optional parameters: none
Encoding considerations: 7bit should always be adequate
Security considerations: see Section 6 of this memo
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 sub-type of the second
body part of the multipart/report.
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 may not have a user agent
capable of interpreting the second section of the multipart/
report. The text in the first section may be in any MIME
standards-track media type, charset, or language. Where a
description of the error is desired in several languages or
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 may be useful to
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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 may be wasteful of network bandwidth and a variety
of implementation strategies can be used. Generally the sender
should 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.
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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.
The text/rfc822-headers media type is defined as follows:
MIME type name: text
MIME 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 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 6 of this memo.
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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5. IANA Considerations
IANA is directed to update 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].
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6. 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 may 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.
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7. References
7.1. Normative References
[KEYWORDS]
Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", RFC 2119, March 1997.
[MAIL] Resnick, P., "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", RFC 4288, December 2005.
[MIME-TYPES]
Freed, N. and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) Part Two: Media Types", RFC 2046,
November 1996.
[OLD-REPORT]
Vaudreuil, G., "The Multipart/Report Content Type for the
Reporting of Mail System Administrative Messages",
RFC 3462, January 2003.
7.2. 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.
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Appendix A. Acknowledgements
The author would like to thank Ned Freed and Keith Moore for their
input to this update.
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Appendix B. Document History
Changes from draft-kucherawy-rfc3462bis-01 to
draft-kucherawy-rfc3462bis-02:
o Revert to removing the restriction altogether, noting that the DSN
and MDN RFCs re-state it. Thus, removing it here solves MARF's
problem but doesn't impact DSN and MDN. The restriction can be
clarified on those documents in separate efforts.
Changes from draft-kucherawy-rfc3462bis-00 to
draft-kucherawy-rfc3462bis-01:
o Clarify requirement that multipart/report must be the outermost
media type; require it only when generating a report.
o Highlight the forwarding-of-reports problem.
o Limit the constraint to time of report generation.
o Remove "Examples" section.
Changes from RFC3462 to draft-kucherawy-rfc3462bis-00:
o Remove requirement that multipart/report not be contained in
anything.
o Some minor adjustment to use current terminology, such as
distinguishing between a header and a header field.
o More obvious use of the standard normative words.
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Author's Address
Murray S. Kucherawy
Cloudmark
128 King St., 2nd Floor
San Francisco, CA 94107
US
Phone: +1 415 946 3800
Email: msk@cloudmark.com
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