Re: [ietf-smtp] Should we update an RFC if people refuse to implement parts of it ?

[Jiankang Yao <[e-mail]>]

 
From: John C Klensin
Date: 2021-05-26 03:34
To: John Levine; ietf-smtp
Subject: Re: [ietf-smtp] Should we update an RFC if people refuse to implement parts of it ?
 
 
> 
> 
> 
> --On Tuesday, May 25, 2021 14:29 -0400 John Levine
> <[e-mail]> wrote:
> 
> > It appears that John C Klensin  <[e-mail]> said:
> >> It would certainly be appropriate to either revise the spec
> >> or, better from my point of view, create a short applicability
> >> statement that explains the reasoning behind the SHOULD and
> >> the circumstances under which it would be sensible to ignore
> >> it. ...
> > 
> >> The thing that sometimes gets lost in "let's make the spec
> >> conform to what implementations are doing" discussions in this
> >> area is that there is an assumption behind the whole
> >> collection of SMTPUTF8 specs, namely that the world really
> >> wanted non-ASCII addressing and header field values. ...
> > 
> > This may seem like splitting hairs but there is a difference
> > between header fields that users see and fields that they
> > don't.  Message-IDs are still generally ASCII in EAI messages,
> > and I don't see any benefit from making the domain names in
> > trace headers U-labels rather than A-labels.
> > 
> > I'm not getting any pushback on Return-Path which really does
> > need to be UTF-8 is it's an EAI address.  I think the few MTAs
> > that put a FOR clause in the Received header put EAI addresses
> > there, too.
> 
> I recognize the distinction while also realizing that, as you
> know, things often leak.  My recollection (if Jiankang is
> following this, his memory is probably better than mine) 
>is that
> the WG explicitly discussed the issue and concluded that
> U-labels were a better idea than A-labels.  
> 

Yes, I think so. The EAI WG discussed this issue.
Section 3.7.3. Trace Information  encourages to use UTF-8 form.
One reason I think is that trace information will be put into header for human reading. UTF-8 is better for human reading.
A-label is ugly for human reading, but ok for machine reading.


Best Regards
Jiankang Yao