Re: [EAI] Re: From Jari: Re: Your DISCUSS on draft-ietf-eai-framework-05 (fwd)

["Charles Lindsey" <chl at clerew.man.ac.uk>]

On Thu, 08 Mar 2007 03:18:26 -0000, John C Klensin <klensin at jck.com> wrote:

> As mentioned above, "mail storage agent" is not well-defined or
> formally part of the model
>
> > cannot safely assume that agents accessing email storage
>
> It is a little worse than that.  It may use some protocol --
> either LMTP or something that is not standardized in the IETF --
> to deliver to the mail store.  If the mail store, or the path to
> it, doesn't have UTF8SMTP capability, the delivery SMTP server
> is stuck.   Worse, it may deliver messages to different
> addresses (mailboxes) into different message stores using
> different protocols.  If some of them are fully capable of
> handling UTF-8 headers and message content, and some are not, it
> should probably advertise the options ...

If a server advertises UTF8SMTP, then it is ofering a guarantee:

   "Either I will ensure that this messages is handed off, in exactly the  
form received, to some user/mailbox/store/system/whatever that is willing  
to offer essentially the same guarantee;
   OR I will downgrade it before passing it to any  
user/mailbox/store/system/whatever that cannot give that guarantee;
   OR I will send it back up the Return-Path with an explanation that it  
could not be delivered."

This implies, to me, that even if there are internal communications (LMPT,  
porocmail scripts, whatever) for routeing mail for different local-parts  
through different channels, the MTA itself needs to be configured with  
basic information as to which local-parts/channels can offer the UTF8SMTP  
capability. Sounds like a case for a bit of sendmail.cf hacking :-( .

> but it is not clear what
> it should do in the cases in which, e.g., someone has assigned a
> non-ASCII address to a UTF-8-incapable mail store.  That case is
> arguably a configuration error,...

agreed.

--
Charles H. Lindsey ---------At Home, doing my own thing------------------------
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   Web: http://www.cs.man.ac.uk/~chl
Email: chl at clerew.man.ac.uk      Snail: 5 Clerewood Ave, CHEADLE, SK8 3JU, U.K.
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