Subject: Re: SMTP or MIME in Strawman OPES Charter

From: Markus Hofmann <[email-masked]>
Date: Wed, 14 Jul 2004 11:40:59 -0400

Martin,

thanks for the examples.

Now, that makes me think whether we should have a separate *short* 
document about such SMTP related use cases. Our current use case 
document is very much HTTP specific, and something similar for 
SMTP-related use cases might be helpful.

Any thoughts?

-Markus

Martin Stecher wrote:

>>Can someone give a specific example/use case for SMTP commands 
>>adaptation ?
>>
> 
> 
> How about these:
> 
> Use Case 1:
> An MTA at a corporate gateway handles outgoing mail traffic.
> In the "MAIL FROM:" command it gets the sender's email address.
> Before replying to this command (allow/deny) it sends an OCP
> request to an OPES service that checks in the corporate directory
> service whether that employee is allowed to send mails to the
> Internet. Depending on the OCP response the MTA replies in the
> SMTP dialog with allow or deny.
> 
> 
> Use Case 2:
> The other way around.
> The MTA sends OCP requests for all "RCPT TO:" commands for
> incoming messages and asks the OPES service whether the
> recipient exists and is allowed to receive email.
> 
> 
> Use Case 3:
> Sender validation via OPES. OPES service checks sender IP,
> HELO command, resolves the sender address etc.
> This may tell the MTA not to accept the message for delivery.
> Could even be done asynchronously for some parts, i.e. sending
> the OCP request after HELO or MAIL FROM and continuing to
> handle recipients and to receive the mail body. The response
> then needs to be there before the message gets finally accepted.
> 
> 
> Regards
> Martin

---

From: Alex Rousskov <[email-masked]>
Date: Thu, 15 Jul 2004 01:14:40 -0600 (MDT)

> SMTP-related use cases might be helpful.

IMO, a short Use Cases section in the "SMTP adaptation with OPES"
draft would be a better choice. More people will read and benefit from
it that way.

It might make sense to separate SMTP command adaptation draft from
SMTP MIME message adaptation draft, but I am not sure. I would
probably shoot for one draft and split later if we feel like it.

Alex.

---

From: Markus Hofmann <[email-masked]>
Date: Thu, 15 Jul 2004 09:35:08 -0400

> draft would be a better choice. More people will read and benefit from

While I typically prefer to minimize the number of documents, in this 
case a separate use cases draft might help getting an exact 
understanding of the type of services considered in scope. An early 
use cases draft also proofed to be helpful in answering questions 
about the scope of the work (I used our existing use cases draft 
several times in this context).

I'm certainly sensitive to the suggestion of merging it into the 
protoco ldraft, but for now let us add a additional deliverable, and 
if there are strong feelings we can change that in the final version 
of the charter.

I'll send out an updated charter proposal within a few minutes.

> probably shoot for one draft and split later if we feel like it.

I would agree with that.

-Markus

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From: jfcm <[email-masked]>
Date: Thu, 15 Jul 2004 18:12:25 +0200

>probably shoot for one draft and split later if we feel like it.

What if an SMTP command is to be changed due to the content (or simply the 
size or the character set etc.) of the MIME message.

---

From: Alex Rousskov <[email-masked]>
Date: Thu, 15 Jul 2004 22:57:28 -0600 (MDT)

On Thu, 15 Jul 2004, jfcm wrote:

> What if an SMTP command is to be changed due to the content (or
> simply the size or the character set etc.) of the MIME message.

Then we would need a service that adapts SMTP commands knowing MIME
message details. We have an example of that in HTTP: adapting
responses knowing requests. Naturally, only commands that can be
delayed or come after the MIME message can be adapted that way.

The above needs are an argument for _not_ splitting SMTP draft into
commands and MIME adaptation drafts.

Alex.