Hector Santos wrote:
Do you think this and your other points are already covered in 4.5.5 in
particular with the 2nd paragraph?
All other types of messages (i.e., any message which is not required
by a standards-track RFC to have a null reverse-path) SHOULD be sent
with a valid, non-null reverse-path.
No, I don't think so. I don't see anything that explicitly says
that a "proper failure report" is either a 5yz code during the SMTP
session or a non-delivery notification sent to the Return-Path. I mean,
*every* SMTP implementor *knows* this, but I think it should be spelled