Re: [dane] email canonicalization for SMIMEA owner names

Paul Wouters <> Fri, 12 December 2014 02:11 UTC

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Date: Thu, 11 Dec 2014 21:11:42 -0500
From: Paul Wouters <>
To: Nico Williams <>
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Cc: dane WG list <>
Subject: Re: [dane] email canonicalization for SMIMEA owner names
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On Thu, 11 Dec 2014, Nico Williams wrote:

> So maybe we need no canonicalization step at all.
> If I say I'm foo@bar.example, and you type Foo@bar.example into your
> MUA to send me e-mail, you might not reach me.
> That seems fair.

Actually, that is really stupid, seeing that many mobile phones, which
are hard to type on to begin with, auto-capitalize for many reasons. My
phone regularly corrects emails I forward to myself to

No currently maintained implementation of email should support that these
two might be different local users.

> And allows for aliases of any kind.  If I want to
> publish SMIMEA RRs for all possible capitalizations of "foo"
> @bar.example, well I can, and if I don't want to then I don't have to.

A client can lookup the given name, if NXDOMAIN and not all lowercase,
lowercase it and try again.

And someone should write an RFC updating SMTP to not allow
case-sensitivity for different mailboxes so we can stop coming back to
this whenever anyone wants to do anything with email addresses.