[dev] IMP implements a feature "Request Delivery Confirmation"

[Thomas]

Dear IMP developers,

IMP implements a feature "Request Delivery Confirmation", which is not
very useful the way it is present. It is also documented in the
sourcecode of the framework, that the way this is implemented it only
works with sendmail prior to version 8.7.
Later versions of sendmail and other mailclients (courier, exim, ...)
implement the delivery notifications like they are specified in RFC 3461
(RFC 1891).
Would it be possible to use this method to request the notifications?
They do not use an additional RFC2822-Header but pass the request in the
SMTP envelope. For IMP it would mean, that if it transmits the message
by a call to /usr/sbin/sendmail it would have to pass an extra argument
"-N success,delay,fail" to sendmail and if SMTP is used to transmit the
message, IMP would have to check if the DSN extension is advertized by
the server and would have to postfix the "RCPT To:<destination at example.com"
command with " NOTIFY=SUCCESS,DELAY,FAILURE".


Kind regards,

Tom