Re: [EAI] Re: Your DISCUSS on draft-ietf-eai-framework-05

[Tony Finch <dot at dotat.at>]

On Wed, 14 Feb 2007, John C Klensin wrote:
>
> The IETF has never specified what happens between the point at
> which the delivery MTA receives a message and the point at which
> something that a mail reader connects to [...] might pick it up.

I don't think this is entirely true. For example, (2)821 talks about
"final delivery" although I admit that it means little more than
appending a Return-Path: field.

> In particular, suppose one assumes a model based on an intermediate
> "mail store" (that model is _not_ required by anything we now have
> standardized.  We lack protocols or specifications for
>    delivery-MTA -> mail store

LMTP is a counter example. It's experimental rather than standards-track,
and I understand that this is because it's supposedly just a private
arrangement within an organization. However there are multiple
interoperable implementations of LMTP, both clients and servers, and it's
normal for each end of an LMTP connection to be software from different
vendors. This is exactly what standards are supposed to be about. Also,
the "private arrangement" argument is bogus since it also applies to POP
and IMAP, and many other Internet standards.

ODMR also fits somewhere in this space - between the MX and the message
store - though it's closer to the MX than the message store. (LMTP is
closer to the message store than the MX.)

Fortunately the EAI SMTP extension should just work with both LMTP and
ODMR.

>    Format of data in mail store and what metadata are stored.
>    API, primitives, or protocol for accessing the mail store
> from (POP, IMAP, LMAP, and other protocols)

I'm not sure what distinction you are getting at here. IMAP specifies in
some detail the mailbox metadata that MUAs must be able to store and
retrieve, and of course IMAP and POP are protocols for accessing mail
stores. I agree that message store formats and APIs are not topics for
IETF standardization, and this is a good thing - there's plenty of good
competition in the IMAP server space developing more efficient message
store formats.

> On Wednesday, 14 February, 2007 14:33 +0200 Jari Arkko <jari.arkko at piuha.net> wrote:
> >
> > Since the final delivery SMTP server (or, to be more specific,
> > its corresponding mail storage agent) cannot safely assume
> > that agents accessing email storage will always be capable of
> > handling the extensions proposed here, it MAY either provide a
> > downgraded version of the internationalized email to these
> > agents, or specially identify messages that utilize these
> > extensions, or both. In any case, the final delivery SMTP
> > server SHOULD allow the original internationalized forms to be
> > accessed by UTF8SMTP-aware agents without information loss,
> > even if they are also accessed in downgraded form by other
> > agents.

No, this is a job for the message store (i.e. POP or IMAP server) not any
SMTP server. Message delivery into the message store (e.g. over LMTP) must
be internationalized if the message store wants to be able to serve UTF-8
email to MUAs.

Tony.
-- 
f.a.n.finch  <dot at dotat.at>  http://dotat.at/
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