Re: [ietf-smtp] How wrong is this EAI implementation

John C Klensin <> Sun, 21 June 2020 04:36 UTC

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Date: Sun, 21 Jun 2020 00:36:41 -0400
From: John C Klensin <>
To: Keith Moore <>,
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References: <alpine.OSX.2.22.407.2006201429080.28792@ary.qy> <2B0EB3A9E99431F86620038A@[]> <alpine.OSX.2.22.407.2006201823060.29484@ary.qy> <DC26ED76E7E316714AB2B820@[]> <>
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Subject: Re: [ietf-smtp] How wrong is this EAI implementation
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--On Saturday, 20 June, 2020 20:11 -0400 Keith Moore
<> wrote:

> On 6/20/20 7:33 PM, John C Klensin wrote:
>> But, coming back to
>> your original question, I think this is permitted and
>> questions about "wrong" or "broken" are matters of personal
>> opinion.
> About this behavior or EAI in general?

Try reading my first response to John Levine today.

The SMTPUTF8 set of protocols, produced by the EAI WG, recommend
against some things that then allow because the WG knew it
couldn't predict every possible case.  In that regard, the WG's
thinking and conclusions are not much different from the
"operational necessity" language that was put into 5321.   In a
more perfect world, without odd circumstances and with a
competent collection of Protocol Police with wide-reaching
enforcement powers, we would not have done things that way.
There is also a case to be made that the whole idea of non-ASCII
addresses was a bad idea (and non-ASCII domain names probably
were too).  In both cases, the designers were quite aware of
those arguments (and some might even agree) but people were
going to do those things and the question was ultimately not "is
this a good idea" but "do you believe in an interoperable
Internet or not".

Not sure that answers your question.  Even if it does, YMMV.