RFC1892

Network Working Group G. Vaudreuil Request for Comments: 1892 Octel Network Services Category: Standards Track January 1996

               The Multipart/Report Content Type
                      for the Reporting of
              Mail System Administrative Messages

Status of this Memo

This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited.

The Multipart/Report MIME content-type

The Multipart/Report MIME content-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 content-type with respect to delivery status reports, mail processing programs will benefit if a single content-type is used to for all kinds of reports.

The Multipart/Report content-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 4 of this memo.

The syntax of Multipart/Report is identical to the Multipart/Mixed content type defined in [MIME]. When used to send a report, the Multipart/Report content-type must be the top-level MIME content type for any report message. The report-type parameter identifies the type of report. The parameter is the MIME content sub-type of the second body part of the Multipart/Report.

  User agents and gateways must be able to automatically determine
  that a message is a mail system report and should be processed as
  such.  Placing the Multipart/Report as the outermost content
  provides a mechanism whereby an auto-processor may detect through
  parsing the RFC 822 headers that the message is a report.

The Multipart/Report content-type contains either two or three sub- parts, in the following order:

(1) [required] The first body part contains 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 an 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
   content-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 a Message/Report 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) which caused the report to be generated, along with
   details not present in the first body part that may be useful to
   human experts.  An initial body part, Message/delivery-status is
   defined in [DSN]

(3) [optional] A body part containing the returned message or a

   portion thereof.  This information may be useful to aid human
   experts in diagnosing problems.  (Although it may also be useful
   to allow the sender to identify the message 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 [DRPT], the agent which generated the delivery service report should return the full message content.

When data not encoded in 7 bits is to be returned, and the return path is not guaranteed to be 8-bit capable, two options are available. The origional message MAY be reencoded into a legal 7 bit MIME message or the Text/RFC822-Headers content-type MAY be used to return only the origional message headers.

The Text/RFC822-Headers MIME content-type

The Text/RFC822-Headers MIME content-type provides a mechanism to label and return only the RFC 822 headers of a failed message. These headers are not the complete message and should not be returned as a Message/RFC822. The returned headers are useful for identifying the failed message and for diagnostics based on the received: lines.

The Text/RFC822-Headers content-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 RFC822
             headers, however, if the headers are broken and require
             encoding, they may be encoded in quoted-printable.
      Security considerations: see section 4 of this memo.

The Text/RFC822-headers body part should contain all the RFC822 header lines from the message which caused the report. The RFC822 headers include all lines prior to the blank line in the message. They include the MIME-Version and MIME Content- headers.

References

[DSN] Moore, K., and G. Vaudreuil, "An Extensible Message Format for

   Delivery Status Notifications", RFC 1894, University of
   Tennessee, Octel Network Services, January 1996.

RFC822 Crocker, D., "Standard for the format of ARPA Internet Text

   Messages", STD 11, RFC 822, UDEL, August 1982.

[MIME] Borenstein, N., and N. Freed, "Multipurpose Internet Mail

   Extensions", RFC 1521, Bellcore, Innosoft, June 1992.

[DRPT] Moore, K., "SMTP Service Extension for Delivery Status

   Notifications", RFC 1891, University of Tennessee, January 1996.

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.

Author's Address

Gregory M. Vaudreuil Octel Network Services 17060 Dallas Parkway Dallas, TX 75248-1905

Phone: +1-214-733-2722 EMail: [email protected]