Message-ID: <c=US%a=_%p=Microsoft%l=DABONE-960705205443Z-2707@feyuri.microsoft.com>
From: "Sukvinder Singh Gill (Exchange)" <sukvg@exchange.microsoft.com>
To: "'drums@cs.utk.edu'" <drums@cs.utk.edu>,
        "'Barry Finkel'"
	 <b19141@achilles.ctd.anl.gov>
Cc: "'bsfinkel@anl.gov'" <bsfinkel@anl.gov>,
        "'moore@cs.utk.edu'"
	 <moore@cs.utk.edu>
Subject: RE: Multiple 'To:" fields 
Date: Fri, 5 Jul 1996 13:54:43 -0700
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>When the cc:Mail SMTP gateway receives the 550 reply to the second RCPT TO
>command, the gateway returns the mail to the sender as undeliverable.  The
>gateway does not send the mail to the valid recipients.  Is this cc:Mail
>gateway software violating the SMTP RFC?
>

Per RFC 821, they are not in violation. 821 does not state what SHOULD
happen in this scenario. Basically in your example earlier, one
recipient could have been delivered to, and the other could not. The
Sender SMTP choose to NDR the message for all recipients, BUT, it
should indicate which recipient(s) that caused the MTA to NDR the
message. If it NDRs the message as undeliverable for all recipients
then this is a bad thing, since it provides the sending user no idea
why the message could not be delivered.
Some MTAs choose to send the message and only generate an NDR for the
recipients that failed. Others choose to NDR the entire message, and
indicate which recipients had problems.

It SHOULD be a requirement if its not documented anywhere that the MTA
that generates the NDR MUST indicate the recipients that could not be
delivered to.
IMO opinion, I think users would only want an NDR for the recipient's
that failed, since its easier to understand. But this is just my
opinion.

-Suki