At 07:50 16-01-2008, Frank Ellermann wrote:
The sender can't fix any problems between "forwarder" and
"receiver" (or next "forwarder"), the complete concept of
"forwarding to 3rd parties" is utter dubious (after 1123).
You may be right but it still won't be right unless the other
participants agree with your point of view.
+1 agreeing with Frank's POV.
Section 4.4 (Trace Information) mentions that
any further (forwarding, gateway, or relay) systems MAY remove the
return path and rebuild the MAIL command as needed to ensure that
exactly one such line appears in a delivered message.
However, the previous section 3.9.1. (Alias) recommends that
To expand an alias, the recipient mailer simply replaces the pseudo-
mailbox address in the envelope with each of the expanded addresses
in turn; the rest of the envelope and the message body are left
Assuming that SMTP doesn't need to delve into boundaries and complex
network topologies, the best it can do is to refer to current best
practices. E.g, like so:
To expand an alias, the recipient mailer replaces the recipient
address in the envelope with each of the expanded addresses in
turn. Trace information SHOULD be removed and the envelope sender
address SHOULD be changed according to local forwarding policies,
or left intact in case of lack thereof.