Quoth Philip Hazel on Thu, Feb 17, 2000:
> On Thu, 17 Feb 2000, John Horne wrote:
> > However, in our case, and as pointed out by Jonathan Hunter,
> > 'forwarding' here is referring to the user actually reading the message and
> > deliberately clicking the 'forward' button to send the message to another
> > user.
*boggle*
John, can you please tell me which MUA it is, so I'll know to
avoid it in the future?
> Oh! That's a completely different kettle of fish. In that case, I would
> say that a reasonable MUA should "normally" resend a new message, with a
> new envelope sender. The user should need to take special action to
> achieve the "bounce" feature.
Usually (i.e., in sane MUAs) "bounce" adds Resent- headers and
changes the envelope to match them.
> Indeed, if the MUA is unprivileged and the
> MTA is Exim running on the same host,
... and the MUA sends mail by running Exim and piping the message
into it, as opposing to talking to Exim via SMTP ...
> the MUA *cannot* adjust the envelope recipient.
ITYM s/recipient/sender/.
> Example: on this host, I run Pine. I can "forward" - which wraps the old
> message in a new one, or "bounce", which does not. However, even if I do
> "bounce" - i.e. I resend the old message unchanged, the envelope
> recipient gets set to me.
Exactly.
> The problem, of course, is when the MUA is running on a different host;
> the MTA can't do the same kind of checking. (And some don't check.)
Anyway, MUAs should _not_ set the envelope sender to the sender
of the original message, whether when forwarding or when
bouncing. Just because the sole purpose of the envelope sender
is to know where to send error messages.
It's also a privacy measure. If I forward (or bounce, or
whatever) your mail to a friend of mine, and the mail can not be
delivered for some reason, I _don't_ want you to know that I
forwarded your mail somewhere. _And_ I want to know that it
failed.
> "If this is a delivery failure ($sender_address is empty) and there
> is a Resent-from: header, and the address in the resent-from header
> is one of our local users, then change the recipient address to that
> value"
Sick. It can be implemented, but shooting the guys (and girls)
who wrote that MUA is probably not easier, but certainly the
right thing to do.
Vadik.
--
A fool's brain digests philosophy into folly, science into
superstition, and art into pedantry. Hence University education.
-- G. B. Shaw
