At 19:28 +0000 on 10/28/2011, Rosenwald, Jordan wrote about Re: SMTP
traffic control:
Perhaps I missed something (this has been a long thread), but I'm
completely missing how this will solve the problem of long,
unpredictable delays for users. Everything I've read says these are
return codes for server consumption, not to be returned to users.
As best I can tell this proposed idea does nothing for the end user.
Once the end user has handed their message over to the MSA they are
out of the loop in any case - The MSA has accepted the message for
delivery/forwarding and there is nothing more that the user can/needs
to do. The only time that the user's submission attempt is impacted
is if the MSA is Graylisting their MUA Client. Once the MSA has
accepted responsibility for the message, the user assumes that it
will rapidly be delivered to its ultimate destination. The user
benefits since the MSA (and intermediate forwarding MTAs) are given
the information needed to pass the message on as rapidly as possible
(ie: Pass it on as soon as the next MTA in the chain is willing/able
to accept responsibility for the message).