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

"John R Levine" <johnl@taugh.com> Thu, 10 January 2019 20:48 UTC

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Date: Thu, 10 Jan 2019 15:48:00 -0500
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From: John R Levine <johnl@taugh.com>
To: John Bucy <jbucy@google.com>
Cc: ietf-smtp <ietf-smtp@ietf.org>
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Subject: Re: [ietf-smtp] [Proposal] confusing parts of the mail system, was 250-MARKDOWN
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On Thu, 10 Jan 2019, John Bucy wrote:
>> For systems that have separate MUA and MTA, the MUA has no way to tell
>> whether a downstream recipient will support BINARYMIME
>
> 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.

It is my impression that some do, but most don't.  There isn't an SMTP 
error code for "downstream recipient doesn't accept BINARYMIME" so we'd be 
talking about a great deal of duct tape to make that work.

Rather than do that, I'd rather do different duct tape that stores the 
giant blob on an external server via soemthing like drive, box, or 
dropbox, and puts a message/external-body part into the message.  See RFC 
2017.

Regards,
John Levine, johnl@taugh.com, Taughannock Networks, Trumansburg NY
Please consider the environment before reading this e-mail. https://jl.ly

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