Re: [idn] WG last call documents

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

"Adam M. Costello" wrote:
> 
> "D. J. Bernstein" <djb@cr.yp.to> wrote:
> 
> >    * RFC 1035, section 2.3.3, quite explicitly allows administrators
> >    to store case-sensitive data in the domain name system
> 
> You can't have foo.com and Foo.com refer to different information.

As owner names, those labels will be treated the same for comparison
purposes. As owner names of RRs which are provided as supplemental data
(such as CNAME completion, NS RRs in Authority, etc) the capitalization
will be preserved. As RR data, their capitalization will be preserved.

> If you have case-sensitive names that you're trying to map onto
> domain names, you're going to run into that limitation.  Domain names
> may be case-preserving to some extent, but they do not accomodate
> case-sensitive names.

The case-sensitive data-types which are normally found in DNS do not
normally exist as owner domain names. For example, there are no RRs that
use mailboxes as owner domain names. However, as M Andrews pointed out in
<200111220358.fAM3wVo45784@drugs.dv.isc.org>, this has not always been the
situation and it isn't guaranteed to always be the situation in the future
either. Mandatory lowercasing on all i18n domain names would be
counter-productive in that scenario as well.

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