On Fri, Mar 26, 2004 at 02:45:52PM +0100, Arnt Gulbrandsen wrote:
bz writes:
If you want to give an error message to the party who actually sent
you the e-mail you need to know the real 'reverse path'. This may
have nothing to do with the SMTP client the message was receive from.
You're assuming that there _is_ a reverse-path for the sending party.
For a lot of mail here isn't, particularly the sort of mail most people
want to reject (spam and virii).
But there is a TCP connection to the sending SMTP client. That TCP
connection is real and dependable. An SMTP server can use that TCP
connection to give an error message, and it will _not_ be giving that
error message to some unfortunate bystander.
Well, in some cases it *will* namely when some MTA has accepted a
message and it sending it forward on behalf of some .forward or mail
list scheme. Maybe that is bad practice, but it happens all the time.
I think we should try to list existing practice, with a number of
frequent scenarios, and then give some advice in each case on how the
MTA could/should handle this.
best regards
keld