Commit | Line | Data |
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2117e02e MW |
1 | Notice-Requested-Upon-Delivery-To (NRUDT) |
2 | D. J. Bernstein, djb@pobox.com | |
3 | 19970201 | |
4 | ||
5 | ||
6 | 1. Introduction | |
7 | ||
8 | The UNIX sendmail program has for many years supported a | |
9 | Return-Receipt-To (RRT) header field that requests a notice of | |
10 | successful final delivery. | |
11 | ||
12 | Notice-Requested-Upon-Delivery-To (NRUDT) has the same basic | |
13 | function. The big difference is that RRT lists the sender's address, | |
14 | while NRUDT lists the recipient's address. | |
15 | ||
16 | This change is critical. RRT works poorly for messages to multiple | |
17 | recipients, because it requests a notice from every recipient. RRT in | |
18 | a message to a large mailing list produces a giant, usually | |
19 | unintentional, flood of mail. This problem is so severe that RRT has | |
20 | been disabled in recent versions of sendmail. | |
21 | ||
22 | NRUDT is designed to be adopted immediately, with minimal disruption, | |
23 | as a solution to the problems of RRT. Note that NRUDT is merely a | |
24 | request for notification; unlike the link-level Delivery Status | |
25 | Notification SMTP extension, NRUDT does not provide a guarantee of | |
26 | notification. | |
27 | ||
28 | NRUDT is supported by the qreceipt program in the qmail package. | |
29 | ||
30 | ||
31 | 2. Syntax | |
32 | ||
33 | NRUDT is a field in the header of an RFC 822 mail message. It has the | |
34 | following syntax: | |
35 | ||
36 | "Notice-Requested-Upon-Delivery-To" ":" 1#address | |
37 | ||
38 | See RFC 822 for more information about header fields and addresses. | |
39 | ||
40 | NRUDT requests that, upon final delivery of the message to any of the | |
41 | specified addresses, the sender be notified. Note that more than one | |
42 | address can appear in a single NRUDT header field. Multiple NRUDT | |
43 | header fields should not appear in a single message. | |
44 | ||
45 | ||
46 | 3. Response | |
47 | ||
48 | Upon successful final delivery of a message to any address listed in | |
49 | an NRUDT header field, the host performing delivery may, if desired, | |
50 | generate a success notice. | |
51 | ||
52 | The success notice is similar to a failure notice as described in RFC | |
53 | 1123. Its envelope sender is <>. Its envelope recipient is the | |
54 | envelope sender of the original message; however, if the envelope | |
55 | sender of the original message is <>, a success notice is not sent. | |
56 | ||
57 | The body of the success notice does not contain a copy of the | |
58 | original message, but it does indicate the Message-ID of the original | |
59 | message, as well as the relevant recipient address. | |
60 | ||
61 | A success notice may indicate delivery to several addresses. For | |
62 | example, given the following message: | |
63 | ||
64 | (envelope) from djb@silverton.berkeley.edu | |
65 | (envelope) to god@heaven.af.mil, angels@heaven.af.mil | |
66 | Date: 1 Jan 1996 21:43:34 GMT | |
67 | From: "D. J. Bernstein" <djb@silverton.berkeley.edu> | |
68 | Message-Id: <19960101214334.8529.qmail@silverton.berkeley.edu> | |
69 | Notice-Requested-Upon-Delivery-To: God <god@heaven.af.mil>, | |
70 | angels@heaven.af.mil (You Know Who You Are) | |
71 | ... | |
72 | ||
73 | a host may respond as follows: | |
74 | ||
75 | (envelope) from <> to djb@silverton.berkeley.edu | |
76 | Date: 1 Jan 1996 21:43:37 GMT | |
77 | From: DELIVERY NOTICE SYSTEM <MAILER-DAEMON@heaven.af.mil> | |
78 | To: djb@silverton.berkeley.edu | |
79 | Subject: success notice | |
80 | ||
81 | I delivered <19960101214334.8529.qmail@silverton.berkeley.edu> | |
82 | to the following local mailboxes: | |
83 | ||
84 | god@heaven.af.mil | |
85 | angels@heaven.af.mil | |
86 | ||
87 | Thanks for asking. | |
88 | ||
89 | However, a success notice is never merged with a failure notice. |