Re: [regext] [Last-Call] last call reviews of draft-ietf-regext-epp-eai-12 (and -15)

John C Klensin <> Tue, 13 September 2022 19:04 UTC

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Date: Tue, 13 Sep 2022 15:03:57 -0400
From: John C Klensin <>
To: "Gould, James" <>,
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Subject: Re: [regext] [Last-Call] last call reviews of draft-ietf-regext-epp-eai-12 (and -15)
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My apologies for not having responded to your note sooner.
I've been preoccupied with several unrelated things.

I greatly appreciate the changes to use an existing EPP
extension framework and to correct the terminology error of EAI
-> SMTPUTF8.   I agree that the more substantive SMTPUTF8
technical issues should go back to the WG.

However, in order that the discussion you suggest for IETF 115
be useful and not just lead to another round of heated Last Call
discussions, I think that, for the benefit of those who have
been following the discussion closely and those who should have
been, it is important to be clear about what the disagreement is
about.  When you characterize the issue as "e-mail cardinality",
it makes it sound, at least to me (maybe everyone in the WG has
a better understanding) like this is some subtle technical

It really isn't.  The EAI WG was very clear during the
development of the SMTPUTF8 standards that the biggest problems
with non-ASCII email addresses were going to be with user agents
(MUAs) (and, to some degree, with IMAP and POP servers that are
often modeled as part of MUAs) and not with SMTP transport over
the Internet.  Making an MUA tailored to one particular language
and script (in addition to ASCII), or even a handful of them, is
fairly easy.  Making one that can deal well with all possible
SMTPUTF8 addresses is very difficult (some would claim
impossible, at least without per-language, or
per-language-group, plugins or equivalent).  

The implication of that problem is that, except with rather
specific constraints, fallback all-ASCII addresses are
important.  I'd be delighted to have a discussion about the
types of constraints the would be needed, but every possibility
involves a policy decision about DNS registration management and
is hence out of IETF scope.  I claim didn't take the EAI WG to
figure the need for fallback addresses out: it gets fairly easy
as soon as someone thinks about, e.g., how their favorite MUA
would manage addresses, and potentially error messages, that use
a relatively complex writing system that has not been in active,
non-scholarly, use for millennia. 

This is why, unless non-ASCII email addresses are used strictly
within a particular writing system environment (and restricted
to those writing systems), it is strongly recommended that an
all-ASCII email address be available as a fallback.  

As we have discussed, I am not suggesting such an address be
required in any particular transaction any more than you are
suggesting that registries be required to accept non-ASCII email
addresses at all.  Subject to whatever regulatory, contractual,
or other constraints might apply, decisions about whether to
allow (or encourage) such addresses, what constraints to impose
on the scripts or domains that might be used in the addresses if
any, and whether a all-ASCII address (or an all-ASCII local
part) should be allowed or required in a particular transaction,
is not a matter for the IETF.  

However, providing for the optional transmission of a non-ASCII
address without providing for the optional transmission of an
all-ASCII alternative is as much of a policy decision as trying
to build rules about when non-ASCII addresses should be
permitted would be.  If the IETF (or at least REGEXT) believe
that it is a good idea to provide for non-ASCII addresses, let's
do that right.  And "right" requires either provision for a an
all-ASCII alternative or a globally agreed profile of what sorts
of non-ASCII addresses are valid.  It is not the sort of thing
that can reasonably be ignored or postponed for future work, at
least without creating back-door policy decisions and/or
interoperability problems, or the IETF is willing to standardize
a protocol with known serious deficiencies on the assumption
that those "details" can be worked out later.


--On Wednesday, August 31, 2022 17:26 +0000 "Gould, James"
<> wrote:

> John, 
> draft-ietf-regext-epp-eai-16 was posted that addresses two of
> the issues that you raised, by changing to use a
> command-response extension, and to replace the EAI references
> with SMTPUTF8.  I believe the remaining issue of the e-mail
> cardinality needs to be brought back to the REGEXT working
> group for discussion.  I've requested an agenda item at
> IETF-115 for it and I encourage you to participate in the
> meeting to discuss it first-hand if the agenda item is
> accepted.
> Thank you for all your detailed feedback and discussion!