Subject: Small comment on 3028bis redirect

From: Aaron Stone <[email-masked]>
Date: Wed, 14 Jun 2006 08:59:28 -0700

I'm reading over the redirect action, and it makes reference to the
behavior of "a .forward file using sendmail under UNIX."

Could the intended behavior be made explicit? I'd to know if the
envelope sender on the new outgoing message should be the Sieve
recipient or the original sender.

And uh, since it seems somewhat obvious now that I think about it that
it cannot be the original sender, who is not likely to be vouched for by
the relaying MTA if, say, there's an SPF query... probably best to
clarify the language in that paragraph in section 4.2 of 3028bis.

Aaron

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From: Ned Freed <[email-masked]>
Date: Wed, 14 Jun 2006 14:22:59 -0700 (PDT)

> recipient or the original sender.

This is implementation and situation dependent. There are reasons why the MAIL
FROM address may need to change and reasons why it may need to stay the same.

One factor is whether or not sieve acts before, during, or after final
delivery. If actions are taken prior to final delivery there's a good argument
to be made that redirect is equivalent to an MTA forward and the MAIL FROM
address and envelope id should not change. If, OTOH, redirect is done
client-side after final delivery there's a good argument to be made that you're
dealing with  a new submission to the transfer system and the message needs to
have a new MAIL FROM and envelope id.

> clarify the language in that paragraph in section 4.2 of 3028bis.

The fact that SPF has issues in this regard is one of the reasons why it is an
experimental specification, not standards track. SPF doesn't play very nicely
with many sorts of MTA-level forwarding, including but not limited to some
implementations of sieve redirect. Some of these types of forwarding have been
part of email pretty much since the beginning. THis is why SRS exists, after
all.

In any case, while I would have no problem with adding some discussion of this
issue, I would strongly object to any recommendation that the MAIL FROM address
MUST, MUST NOT, SHOULD, or SHOULD NOT change.

				Ned

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From: Kjetil Torgrim Homme <[email-masked]>
Date: Wed, 14 Jun 2006 23:42:14 +0200

> recipient or the original sender.

it is the original sender.  after all, it wouldn't do much good to send
the error report to the recipient, since he has forwarding set up :-)
the alternative would have to be the local postmaster, but that would be
a novel way of handling it, and novel solutions usually come back to
bite you.

> clarify the language in that paragraph in section 4.2 of 3028bis.

that's why SPF is broken and never will be a standard.

I agree the behaviour needs to be stated explicitly.
-- 
Kjetil T.

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From: "Aaron Stone" <[email-masked]>
Date: Wed, 14 Jun 2006 22:09:51 -0000

On Wed, Jun 14, 2006, Ned Freed <[email-masked]> said:

> This is implementation and situation dependent. There are reasons why the
> MAIL FROM address may need to change and reasons why it may need to stay
> the same.
> 
> delivery. If actions are taken prior to final delivery there's a good
> argument to be made that redirect is equivalent to an MTA forward and
> the MAIL FROM address and envelope id should not change. If, OTOH, redirect
> is done client-side after final delivery there's a good argument to be made
> that you're dealing with  a new submission to the transfer system and the
> message needs to have a new MAIL FROM and envelope id.

After some more searching (your keywords "MTA foward" were golden) I found
this early discussion (Google archive because gmane is broken right now)

http://72.14.203.104/search?q=cache:2SK_eTCQbMYJ:blog.gmane.org/gmane.ietf.mta-filters/month%3D19970701+mta+forwarding&hl=en&gl=us&ct=clnk&cd=10&client=firefox-a

Basically the same thing as you just wrote above was also used to clarify
the same question back in 1997. Perhaps the clarifying text should be
inserted into the draft, using keyword MAY to explain how the different
environment Sieve runs in MAY effect the redirect action.

Aaron

--

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From: Ned Freed <[email-masked]>
Date: Wed, 14 Jun 2006 15:58:44 -0700 (PDT)

> environment Sieve runs in MAY effect the redirect action.

Sounds good to me.

				Ned