Subject: Re: [Uta] SMTP Over TLS on Port 26 - Implicit TLS Proposal
From: "John Levine" <[email-masked]>
To: [email-masked]
Cc: [email-masked]
Date: 8 Jan 2019 09:57:25 -0500
List-Id: UTA working group mailing list <uta.ietf.org>

In article <[email-masked]> you write:
>MX servers would not be violating RFC if they rejected plain text 
>connection attempts (over 90% of which these days are spam).

10% is a pretty fat long tail.  The people I know who run production
mail systems are much more concerned about receiving all of the real
mail than rejecting spam earlier.

We went through all of this when we invented MTA-STS.  We know that
setting up a web server can be non-trivial but for a lot of places,
it's far easier than geting DNSSEC to work.  I recall a dinner at the
Buenos Aires IETF where we were trying to figure out if there were a
reasonable way to signal stuff in the DNS.  Magic names certainly came
up.

I think it would be a good idea for anyone interested in this topic to
go back through the mailing list discussion and read the drafts and
explain what is different now that we didn't know when we defined
MTA-STS a few months ago.

R's,
John