Re: [idn] Needed changes to IDNA before last call

["Adam M. Costello" <idn.amc+0@nicemice.net.RemoveThisWord>]

Dan Oscarsson <Dan.Oscarsson@trab.se> wrote:

> I suggest the following is done:
> 
> The draft: idn-nameprep
> Title change: Stringprep profile for Internationalised DNS labels.

I agree, except that I would recommend "Stringprep Profile for
Internationalized Domain Names", to be consistent with the title of the
IDNA draft.

> The draft: idn-idna:
> The ToASCII must be applied to ALL labels containing non-ASCII.

Rule 1 already says:

    Whenever a domain name is put into a generic domain name slot, every
    label MUST contain only ASCII characters.

"every label".

> The steps need a slight change:
>  - character restrictions will apply depending on label, it could be
>    host name or e-mail name.

Step 3 of ToASCII already says "If the label is part of a host name (or
is subject to host name syntax rules) then perform these checks".

When you say "e-mail name" do you mean the local part (before the @)?
That's outside our jurisdiction.  Another working group will have to
decide how to internationalize email local parts.  We can only tell how
to deal with domain names.

You may be concerned about resource records that contain email addresses
represented as domain names (with the local part as the first label).
Currently there is no problem, because all email address local parts are
ASCII according to RFC 2822.

>  - Encoding into ACE must use Punycode WITH case marking so that
>    case can be restored when using ToUnicode.
> 
> ToUnicode is fine, but decoding Punycode must restore case.

I have already argued for mixed-case support as best I can.  I couldn't
quite get it *mentioned* in the IDNA and Nameprep documents.  You don't
have a prayer of getting it *required*.

Of course, the working group that internationalizes email local parts
would have the option of writing a spec that requires Punycode with
mixed-case support.

AMC