Re: [ietf-smtp] Possible cont4ibution to moving forward with RFC5321bis SMTP

[Keith Moore <[e-mail]>]

On 12/26/19 4:30 PM, John C Klensin wrote:

> I also interpret some recent work and statements
> within the IETF as leading toward prohibiting email that is not
> encrypted hop-by-hop on the grounds of privacy protection not
> anti-spam efforts.

As sympathetic as I am to the privacy issue, I'd have a difficult time 
supporting a general requirement to encrypt all mail relaying because of 
backward compatibility issues with hosts that don't have TLS support yet 
(including IIoT-related concerns).

I also think that any SMTP upgrade will quite naturally have a long 
tail, so imposing any global requirement (even if it earned broad 
support) without breaking mail that people need to continue to have 
delivered, would be quite a technical challenge.

To me it seems that all of this should be out-of-scope for 5321bis, or 
that the only mention of this in 5321bis should be to declare such 
things out-of-scope.   Requiring hop-by-hop encryption would be the most 
disruptive change in the history of SMTP, I think, far more so than EHLO.

Keith