John C Klensin wrote:
As part of the issue 16 cleanup (changing informal statements
about requirements to more formal, 2119-like, language), the
critical text about receiver responsibility for messages they
accepted was changed from
The responsibility of an SMTP client is to transfer mail
messages to one or more SMTP servers, or report its
failure to do so.
In either case, a formal handoff of responsibility for
the message occurs: the protocol requires that a server
MUST accept responsibility for either delivering a
message or properly reporting the failure to do so.
I see two issues with this text, suggesting the need for some added
text. It's not that there is anything "wrong" with the proposed text,
but that it is missing some detail, and certainly none of this would
change SMTP semantics:
1. A server is not "always" required to accept responsibility. Rather,
it is required to accept responsibility after issue a success response
to some part of the protocol. Until it issues that response, it is NOT
responsible for the message; the client is.
2. In other words, what is missing is reference to the state-change that
carries the formal transfer of responsibility from client to server --
and it needs to be stated in terms of both client and server I assume
that it is a 250 reply to DATA, but wouldn't stake my life on that.