Re: [idn] WG last call documents

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

"D. J. Bernstein" <djb@cr.yp.to> wrote:

> > If you have case-sensitive names that you're trying to map onto
> > domain names, you're going to run into that limitation.
>
> False.  I have already given an example: the mailbox name stored in an
> SOA record.

Okay, there you can get away with it because that domain name is never
the name of a record in the DNS, it is only part of the returned
data.  Names of records (that is, names that can be queried) are
case-insensitive.

> > Domain names may be case-preserving to some extent, but they do not
> > accomodate case-sensitive names.
>
> RFC 1035, section 2.3.3, final paragraph, clearly and explicitly
> allows case-sensitive names in DNS.  It even uses the words
> ``case-sensitive.''  Are you completely unable to read?

Are you?  Here's the paragraph you refer to:

    Systems administrators who enter data into the domain database
    should take care to represent the data they supply to the
    domain system in a case-consistent manner if their system is
    case-sensitive.  The data distribution system in the domain system
    will ensure that consistent representations are preserved.

Nowhere does that paragraph apply the term "case-sensitive" to the
names.  It applies to term "case-sensitive" to the system on which the
database resides.  It's warning administrators not to accidentally enter
both "foo" and "Foo" into the database if their database would blindly
do that, because the DNS database is not allowed to have both "foo" and
"Foo" in the same zone.

It says that the DNS will preserve the case of whatever was entered,
but as I explained above, that doesn't mean the DNS can accomodate
case-sensitive names of records.  If I have a collection of
case-sensitive names, it might contain names that differ only in their
case, and DNS will not make the distinction.

AMC