RFC 1891 (rfc1891) - Page 2 of 31
SMTP Service Extension for Delivery Status Notifications
Alternative Format: Original Text Document
RFC 1891 SMTP Delivery Status Notifications January 1996
the SMTP MAIL command), containing an explanation of the error and at
least the headers of the failed message.
Experience with large mail distribution lists [3] indicates that such
messages are often insufficient to diagnose problems, or even to
determine at which host or for which recipients a problem occurred.
In addition, the lack of a standardized format for delivery
notifications in Internet mail makes it difficult to exchange such
notifications with other message handling systems.
Such experience has demonstrated a need for a delivery status
notification service for Internet electronic mail, which:
(a) is reliable, in the sense that any DSN request will either be
honored at the time of final delivery, or result in a response
that indicates that the request cannot be honored,
(b) when both success and failure notifications are requested,
provides an unambiguous and nonconflicting indication of whether
delivery of a message to a recipient succeeded or failed,
(c) is stable, in that a failed attempt to deliver a DSN should never
result in the transmission of another DSN over the network,
(d) preserves sufficient information to allow the sender to identify
both the mail transaction and the recipient address which caused
the notification, even when mail is forwarded or gatewayed to
foreign environments, and
(e) interfaces acceptably with non-SMTP and non-822-based mail
systems, both so that notifications returned from foreign mail
systems may be useful to Internet users, and so that the
notification requests from foreign environments may be honored.
Among the requirements implied by this goal are the ability to
request non-return-of-content, and the ability to specify whether
positive delivery notifications, negative delivery notifications,
both, or neither, should be issued.
In an attempt to provide such a service, this memo uses the mechanism
defined in [4] to define an extension to the SMTP protocol. Using
this mechanism, an SMTP client may request that an SMTP server issue
or not issue a delivery status notification (DSN) under certain
conditions. The format of a DSN is defined in [5].
Moore Standards Track