Re: [idn] I-D ACTION:draft-ietf-idn-nameprep-07.txt

["Eric A. Hall" <ehall@ehsco.com>]

"Adam M. Costello" wrote:
> 
> Yves Arrouye <yves@realnames.com> wrote:

> > why bother with the 0000-0020 and 007F
> 
> I've wondered about that myself.  The nameprep draft gives the reasons
> for all the prohibited code points.  I'm not sure how convincing all the
> reasons are, but you can look at them and judge for yourself.

I haven't yet had a chance to go through the latest drafts (other
deadlines) so this is coming from a slightly ignorant perspective, but I
would ask that the IDNA team re-evaluate their position on this matter.

First of all, those code-points should not be universally prohibited,
since they are absolutely legitimate in STD13 domain names. ANY octet
value is allowed. If you are going to be moving SOME of the prohibited
characters from nameprep to the IDNA hostname processing, then you need to
move ALL of them at that stage.

However, this is not the approach I would recommend. Instead, I would
recommend that a series of nameprep-like documents be prepared under the
stringprep umbrella, with one document for each of the known data-types.
For example, there should be a document for i18n hostnames, there should
be another document for STD13 hostnames (to act as an IDNA output filter),
another document for current RFC 2822 email addresses, and so forth. Each
of these documents can then be used as data-type inputs. Or to put it in
another perspective, each of them can be treated somewhat like Unicode
"property" tables, with certain types of output only being allowed to
contain characters from the relevant property.

I'm sure that somebody will say something about this being too late, but
there you have it. At the very least, you should consolidate the
prohibited characters into IDNA, as the prohibited characters which appear
to be in nameprep are in fact valid for STD13 domain names.

I will try to read the last-call drafts and make more informed commentary
tomorrow or Friday.

-- 
Eric A. Hall                                        http://www.ehsco.com/
Internet Core Protocols          http://www.oreilly.com/catalog/coreprot/