Re: [EAI] [IETF] Multiple Addresses [ was: Internationalized Email Internet Draft]

John C Klensin <> Wed, 19 October 2016 13:25 UTC

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Date: Wed, 19 Oct 2016 09:25:10 -0400
From: John C Klensin <>
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Cc: Harish Chowdhary <>,
Subject: Re: [EAI] [IETF] Multiple Addresses [ was: Internationalized Email Internet Draft]
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--On Friday, October 14, 2016 15:07 +0000 wrote:

>> (4) Multiple addresses for one user (and Section 4). 
>> Keeping in mind that many people maintain a number of
>> identities, and even multiple email addresses, for different
>> purposes, I >don't understand what point you are trying to
>> make with this section. 

> Sure.  People have multiple email addresses for different
> reasons.   The question was actually with aliases.  Maybe it
> is not possible to have all email consolidated to one box. For
> example, if I want to have two mailboxes:
> and नलिनी
> (or नलिनी@[myidnserver].[myinternationaltld]) all
> come to one mailbox is that possible?   Should it be possible?
> I *think* people want that.   I think we will know as this
> all takes off.

One more comment on this.  I'm encouraged by John Bucy's comment
that Gmail will support this and I hope the other large
providers will too.  However, to put your question in
perspective, ability to create aliases for mailbox names has
been common in Internet email systems (and supported by every
publicly-available one I have encountered) for a very long time.
>From the perspective of the SMTP specs, even having upper and
lower case ASCII match in the local-part is an aliasing issue,
not a fundamental requirement or transformation.   Expanding an
otherwise well-designed and "8 bit clean" mail delivery system
and server to treat an incoming non-ASCII local-part as an alias
for an all-ASCII one should be simply a matter of modifying the
server to accept non-ASCII local parts and then disabling any
internal syntax checks that prohibit such addresses.

The harder problems lie elsewhere. If the server for
accepts and an alias for, and equivalent
to,, whether Joe's MUA and submission
servers will allow sending from the former address form is a
matter for those servers, not the mailbox name or delivery
systems.  Some will, some won't.  Similarly, there are a few
different ways to handle aliases in terms of what, if anything,
is done to the message headers.  One can imagine a number of
interesting issues in IMAP / POP interfaces or in receiving MUAs
and that number increases when non-ASCII addresses are added in.

> Can you point me to some of that work? 

In (non-IETF) tutorials about Internet email and documents for
specific systems, yes.  Other than a comment here and there
(with case sensitively as a good example), the IETF standards
have deliberated avoided these issues because handling of
mailbox names and aliases are considered to be purely local