On Jun 5, 2006, at 2:29 PM, David Nicol wrote:
The new ESMTP extension is tentatively called "DATAFIRST"
When a server identifies itself as supporting the DATAFIRST extension,
the SMTP transaction may be re-ordered from MAIL FROM, RCPT TO, DATA
to MAIL FROM, DATA, RCPT TO
This would the commit servers into accepting data without being
provided any clue the sender knows who would be available to receive
the information. A better system would seem to be a call-back mode
for the data.
A new ESMTP extension DATA-CALLBACK.
The current DATA phase becomes a the header only portion of the
message. A new header also provides a token used by the MUA to
retrieve the rest of the data. The recipient could check the DKIM
signatures before deciding whether the signing domain had a suitable
reputation before even requesting the information. The bulk of the
message would be held by the sender rather than by the intermediary
for the recipient.
Asrg mailing list