Subject: RE: SMTP or MIME in Strawman OPES Charter

From: "Martin Stecher" <[email-masked]>
Date: Tue, 13 Jul 2004 22:14:43 +0200

> 
> 	Jfc seems to re-visit, perhaps unknowingly, a very important
> charter-related question that we must finish discussing. Please see
> 
> 	http://www.imc.org/ietf-openproxy/mail-archive/msg02979.html
> 
> for the start of the thread. In
> 
> 	http://www.imc.org/ietf-openproxy/mail-archive/msg02982.html
> 
> you said "Similar to what we did in the first charter, we can make
> SMTP the prime goal which we'll have to provide a solution for, but we
> can first explore the feasibility of a general "email/MIME" profile
> (and maybe include an explicit charter item for such exploration)."
> 
> The above direction was supported by Abbie and myself, without
> objections. Can we go down that path and include an exploratory
> charter item instead of starting with SMTP? It may also simplify
> solving the agent-dependency problem for SMTP. We can be more vague
> about SMTP if we have to do MIME first!
> 

In earlier discussions we found that MIME is a good fallback when
negotiating profiles and no match for a more detailed application
is found. So, exploring a MIME profile indeed has some value.

On the other hand I think that we must concentrate on SMTP if we
want to do OPES for email not MIME or any other email protocol.

Most messages in the Internet are transferred using SMTP. POP
and IMAP are used to fetch them from a mailbox but they reach
the mailbox usually via SMTP.

And the SMTP dialog has information that is needed as meta data
in addition to the MIME message for effective filtering, for
example if you want to check the recipients of a message you
better ignore the MIME header but look at the RCPT TO parameters
from the SMTP dialog.

In addition we should consider that some OPES services may want
to adapt the SMTP dialogs, for example control the relay behavior
of an MTA (decide which sender is allowed to send to which recipients).
That is definetly beyond MIME message filtering.

So, I think we should concentrate on OCP/SMTP. As adapting MIME
messages is the most important sub part of that we may want to
explore that first and design the profile in a way that allows to
create an OCP/MIME profile easily by simply deleting all parts that
are beyond the MIME message part.

Regards
Martin

---

From: Alex Rousskov <[email-masked]>
Date: Tue, 13 Jul 2004 17:31:49 -0600 (MDT)

On Tue, 13 Jul 2004, Martin Stecher wrote:

> negotiating profiles and no match for a more detailed application is
> found. So, exploring a MIME profile indeed has some value.
>

Is it reasonable to assume that, due to differences in user agents
(e.g., PC versus phone), folks will want to adapt stored messages when
they know IMAP or POP client preferences (rather then when the message
is received by SMTP server)?

> And the SMTP dialog has information that is needed as meta data in
> addition to the MIME message for effective filtering, for example if
> you want to check the recipients of a message you better ignore the
> MIME header but look at the RCPT TO parameters from the SMTP dialog.

Yes, it is clear that MIME alone is not sufficient for some (most?)
adaptations of e-mails. It is only a common denominator among SMTP,
ICAP, POP.

> That is definetly beyond MIME message filtering.

This is very important, I guess. Should we decide now whether SMTP
commands adaptation is in scope (as opposed to SMTP message
adaptation).

> are beyond the MIME message part.

I see your point (and glad that you are back from vacation!). I have
not decided yet. What are we really trying to optimize here:  Do you
think we will waste a lot of time if we define a common OCP/MIME
profile (that alone will not be useful for some adaptations) and then
build OCP/SMTP profile on top of that (as opposed to building one
monolithic OCP/SMTP profile)? Or do you think that defining a common
OCP/MIME profile is simply useless because nobody cares enough about
IMAP and POP (and so nobody will reuse the common profile).

Thanks,

Alex.

---

From: Markus Hofmann <[email-masked]>
Date: Tue, 13 Jul 2004 21:10:19 -0400

> is received by SMTP server)?

Even if so, let's focus our new charter on SMTP, and we'll have a much 
better chance to get it accepted. This does no preclude us from coming 
up with a solution that might also be useful in the context of IMAP, 
POP or other protocols, but the charter will not require this. Just 
what we did with the initial focus on HTTP and coming up with OCP core.

> commands adaptation is in scope (as opposed to SMTP message

Can someone give a specific example/use case for SMTP commands 
adaptation ?

> IMAP and POP (and so nobody will reuse the common profile).

I don't expect the new charter to make any statements in this regard 
(charter will only request a SMTP profile), so let's first get our new 
charter nailed down and we can then start discussing these details, ok?

-Markus

---

From: Alex Rousskov <[email-masked]>
Date: Tue, 13 Jul 2004 22:32:28 -0600 (MDT)

Markus,

	I am fine with postponing this discussion until the new
charter is approved, with understanding that the new charter does not
limit our option to developing a basic OCP/MIME profile as a
foundation of OCP/SMTP.

Alex.