Re: [ietf-smtp] [Proposal] confusing parts of the mail system, was 250-MARKDOWN

[John Bucy <[e-mail]>]

On Thu, Jan 10, 2019 at 1:07 PM John Levine <[e-mail]> wrote:

> In article <[e-mail]> you write:
> >On Thu, 10 Jan 2019 11:55:53 -0800, John Bucy said:
> >
> >> The MSA could call ahead/cut-through, doesn't exim do that? That might
> also
> >> allow for the mua to throw an error ui at the user if they fat-fingered
> the
> >> recipient rather than getting a bounce back later.
> >
> >No.
> >
> >Consider this reply.  I'm in Comcast cable territory, which means that I
> can
> >only do outbound port 25 to Comcast/Xfinity servers.  So my only realistic
> >way to get this mail out is to 587 it to Google's submission servers.
> >
> >Now how do I "call ahead" for the cc: that's going to John Levine?
>
> The theory is that you submit the whole message to Google and it
> probes the recipients before it accepts the message, but now you have
> the added issue of how to report back that receipient A can handle it
> but recipient B cannot.
>
> I'd really rather the duct tape be applied to make external-body work
> better.
>

Getting the blobs out of band may well be better for large messages. Even
if binary isn't the most compelling case for this, I would like to see a
better way to incrementally roll out new features that require end-to-end
support that is less prone to extended messages leaking out to everyone
else that isn't ready yet.