[Emailcore] Re: [Last-Call] Re: Re: Re: Re: Re: Re: Re: draft-ietf-emailcore-as-28 ietf last call Secdir review

[John Levine <[e-mail]>]

It appears that Christian Huitema  <[e-mail]> said:
>The objection is not that asking that from a software provider would be 
>a bad idea for you. The problem is essentially a shift of 
>responsibilities: the decision to accept clear text message is made by 
>the MTA admin, and the AS would instead create a mandate on all software 
>developers. 

Right. That reflects reality. Mail software and mail systems handle cleartext
mail, and no matter what we say they will continue to do so. We know this
because we have talked to the people who write it and run it and this is what
they have without exception said.

We know from Richard Clayton's recent message that 16% of the hosts that talk to
Yahoo's giant mail system don't do TLS, so any MTA that didn't handle cleartext
mail would not in any meaningful sense interoperate with existing SMTP servers.
Beyond that, John Klensin has pointed out reasons why even if we wanted to turn
off cleartext mail, it would still leak envelope data while often failing
mysteriously.

Why are we even having this argument?

R's,
John