The discussion centers around this DSN (might not be reproduced here in
its original form, since initial poster had inserted his own text into
the middle of the DSN body):
==================
X-From_: BOZO@cs1.presby.edu Sun Feb 8 20:12:06 1998
Return-Path:BOZO@cs1.presby.edu
X-Envelope-To: <fractal@wantree.com.au>
Date: Sun, 8 Feb 1998 12:11:59 GMT
From: BOZO@cs1.presby.edu (Bozo)
Apparently-To: fractal@wantree.com.au
[...]
A T T E N T I O N : Automated reply - will not be repeated.
*******************
The mailbox of the sender (see 'From:' line in this message header)
IS FULL AND CANNOT RECEIVE ANY MESSAGES.
The message you recently sent could not be delivered.
You will receive this message only once. All future messages will be
discarded without notice.
Although we provide a reasonable mailbox quota, it has been exceeded and
we must cut off mail to protect the service for other users. Most
likely, the person went on vacation without unsubscribing from mailing
lists.
If you cannot contact the recipient except by e-mail, you should try again
later, asking that the person confirm that he or she is again reading mail.
Until you get that personal confirmation, ASSUME ALL MAIL IS DISCARDED.
postmaster@presby.edu
==================
The comments:
** Sometime around 11:06 -0500 2/17/98, David W. Tamkin said:
>Frac responded,
>
>| Why? It's up to the subscriber to keep tabs on their subscriptions, not you.
>| Whether a list-member receives mail or not isn't my concern; it's their's.
>| Whether I'm distracted from more important tasks thanks to some bonehead's
>| full mailbox makes it MY problem--I'm not their mama ya know.
>
>Clearly some of the differences between Frac and me on this matter are not
>due to differences in our personalities but to those between our lists. The
::snip::
The bottom line here, IMO, is adherance to RFCs. Failure to return a DSN
("NDN" for those of you who prefer that term) violates RFCs 1891 and 821.
>From RFC1891:
2. Introduction
The SMTP protocol [1] requires that an SMTP server provide
notification of delivery failure, if it determines that a
message cannot be delivered to one or more recipients.
Traditionally, such notification consists of an ordinary
Internet mail message (format defined by [2]), sent to the
envelope sender address (the argument of the SMTP MAIL
command), containing an explanation of the error and at least
the headers of the failed message.
[1] RFC821
Accepting a message for delivery requires the accepting server to return
a DSN in the event that a message is not deliverable, UNLESS THE CLIENT
SPECIFICALLY REQUESTS that a DSN not be returned. To wit, from RFC1891:
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].
[4] RFC1651
[5] RFC1894
Thus, unless specifically requested, it is not acceptable that a DSN not
be returned once a message is accepted for delivery. And since the server
is not bouncing the message immediately, it is, in effect, accepting it for
delivery. This is in direct violation of the relevant RFCs.
There are good reasons to return a DSN in the event of EACH non-delivery;
one of the better ones is that automated bounce handlers will "time out"
the errant address after some time of repeated bouncing. If the DSN is
returned only once, however, the address will not be removed from the
mailing list. This results in wasted bandwidth and potentially-defunct
(for all intents and purposes) addresses remaining on the list.
Overall, the practice of not returning DSNs for individual failures is not
at all clever.
__________________________________________________________________________
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