Hector Santos wrote:
Outlook is a MUA, not a MTA.
All MUAs, including Outlook, have a MTA (SMTP client)
component. How else will it send mail to a SMTP server
I guess the idea here is "ordinary MUAs should NOT talk
with MTAs" (letting them talk with their MSAs of course).
So if we would find that 1xx doesn't work at all in 2821,
- maybe it's just a historic error in (2)821 (?) - then we
could still note this idea for a future 2476ter.
Above all we cannot break unknown portions of conforming
2821 implementations with 2821bis, it would have no chance
in an "IETF last call", let alone the real world.