89 lines
3.3 KiB
Text
89 lines
3.3 KiB
Text
Notice-Requested-Upon-Delivery-To (NRUDT)
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D. J. Bernstein, djb@pobox.com
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19970201
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1. Introduction
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The UNIX sendmail program has for many years supported a
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Return-Receipt-To (RRT) header field that requests a notice of
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successful final delivery.
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Notice-Requested-Upon-Delivery-To (NRUDT) has the same basic
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function. The big difference is that RRT lists the sender's address,
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while NRUDT lists the recipient's address.
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This change is critical. RRT works poorly for messages to multiple
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recipients, because it requests a notice from every recipient. RRT in
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a message to a large mailing list produces a giant, usually
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unintentional, flood of mail. This problem is so severe that RRT has
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been disabled in recent versions of sendmail.
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NRUDT is designed to be adopted immediately, with minimal disruption,
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as a solution to the problems of RRT. Note that NRUDT is merely a
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request for notification; unlike the link-level Delivery Status
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Notification SMTP extension, NRUDT does not provide a guarantee of
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notification.
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NRUDT is supported by the qreceipt program in the qmail package.
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2. Syntax
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NRUDT is a field in the header of an RFC 822 mail message. It has the
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following syntax:
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"Notice-Requested-Upon-Delivery-To" ":" 1#address
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See RFC 822 for more information about header fields and addresses.
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NRUDT requests that, upon final delivery of the message to any of the
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specified addresses, the sender be notified. Note that more than one
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address can appear in a single NRUDT header field. Multiple NRUDT
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header fields should not appear in a single message.
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3. Response
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Upon successful final delivery of a message to any address listed in
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an NRUDT header field, the host performing delivery may, if desired,
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generate a success notice.
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The success notice is similar to a failure notice as described in RFC
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1123. Its envelope sender is <>. Its envelope recipient is the
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envelope sender of the original message; however, if the envelope
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sender of the original message is <>, a success notice is not sent.
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The body of the success notice does not contain a copy of the
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original message, but it does indicate the Message-ID of the original
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message, as well as the relevant recipient address.
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A success notice may indicate delivery to several addresses. For
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example, given the following message:
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(envelope) from djb@silverton.berkeley.edu
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(envelope) to god@heaven.af.mil, angels@heaven.af.mil
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Date: 1 Jan 1996 21:43:34 GMT
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From: "D. J. Bernstein" <djb@silverton.berkeley.edu>
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Message-Id: <19960101214334.8529.qmail@silverton.berkeley.edu>
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Notice-Requested-Upon-Delivery-To: God <god@heaven.af.mil>,
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angels@heaven.af.mil (You Know Who You Are)
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...
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a host may respond as follows:
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(envelope) from <> to djb@silverton.berkeley.edu
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Date: 1 Jan 1996 21:43:37 GMT
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From: DELIVERY NOTICE SYSTEM <MAILER-DAEMON@heaven.af.mil>
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To: djb@silverton.berkeley.edu
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Subject: success notice
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I delivered <19960101214334.8529.qmail@silverton.berkeley.edu>
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to the following local mailboxes:
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god@heaven.af.mil
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angels@heaven.af.mil
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Thanks for asking.
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However, a success notice is never merged with a failure notice.
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