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Re: Bounce/System Notification Address Verification

2005-06-29 22:48:06

At 07:54 -0400 on 06/29/2005, John C Klensin wrote about Re: Bounce/System Notification Address Verification:

--On Wednesday, 29 June, 2005 00:50 -0400 Keith Moore
<moore(_at_)cs(_dot_)utk(_dot_)edu> wrote:

 I am not rejecting anything. All I am suggesting is that when
 more than  one recipient is to be used for the message, to
 generate a separate copy  for each recipient (with only that
 recipient listed as the "To") so  there are separate copies
 (as would occur with multi-recipient [messages  where each
 recipient is in a different domain] at the MTA stage ).

 Why should an MTA or MUA bother to do this?  This part of the
 SMTP standard has been stable since c. 1980 and it has _never_
 required this.
 spammers have consistently shown themselves to be very
 flexible at adapting to far more substantial countermeasures.
 and it's much easier for spammers to adapt than for the vast
 installed base to adapt.  it is counterproductive to impose
 meaningless restrictions on legitimate senders.  in the long
 term this only adds complexity and damages transparency of the
 mail system without doing anything to discourage spam.

And, of course, going to one-recipient-per-message also vastly
increases total transmission time for messages, especially
moderately long messages, in normal use.  That total
transmission time issue -- let's open a minimal number of TCP
connections and transmit the payload on a target host basis, not
a target user one-- is, of course, why the multiple RCPT
provision was included in the mail specs more than a quarter of
a century ago.

Since it is my comment being quoted, I'll respond. My suggestion is ONLY about Mail-From <> messages. These messages are (so far as I can tell) very short Payloads (under 1-2K) and since they will all be queued at the same time will flow back-to-back over the same MTA-to-MTA session (ie: No extra TCP/IP Setup/Teardown overhead). What automatic <> replies that support multiple recipients do you expect to exceed my 1-2K payload size? The "multiple RCPT provision" was instituted for a problem that no longer exists (narrow pipes, long setup/teardown times, and slow transmissions). With the current speeds/bandwidth the extra traffic gets lost in the noise.

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