Re: [imap5] Feature set? - was Re: Designing a new replacement protocol for IMAP

[Tony Finch <[e-mail]>]

Adrien de Croy <[e-mail]> wrote:
>
> > With XSEND, you upload the message to IMAP first, then you say:
> >
> > TAG XSEND UID
>
> how do you provide the SMTP forward path?  Is that scraped from the headers?

That's the right thing to do. You also need to do BCC: processing.
(sendmail -t does the right thing.)

The rationale for BURL is that there is more to the SMTP envelope than
just the sender and recipient addresses - in particular there are the DSN
attributes. There's a somewhat ugly and ill-defined split between
information for MTA processing (in the envelope) and information for MUA
processing (in the headers - see MDN for example). But in fact MTAs do
header processing too, so there no practical advantage to ESMTP envelope
extensions and a lot of complexity disadvantage.

There are a few envelope extensions: DSN, future release, message
tracking, CONNEG and CONPERM facsimile media conversion, and 8BITMIME +
BINARYMIME. If you want to eliminate BURL you need to either define a
mapping from headers to the extension parameters that you want to support,
or embed ESMTP inside IMAP.

Tony.
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