Comments on draft-ietf-idnabis-defs-10
John C Klensin
klensin at jck.com
Mon Aug 31 20:47:26 CEST 2009
--On Monday, August 31, 2009 14:17 -0400 Vint Cerf
<vint at google.com> wrote:
> andrew,
>
> can it be argued that the only way a domain name containing an
> xn- label could be formally registered in the DNS with upper
> case ASCII present would be through violation of the
> IDNA2008 protocol specs? In a strange way, while one would
> actually find and match such a domain name because of DNS
> rules, that object, if returned with its upper case
> components, would fail to convert to a proper U-label.
> Somewhere in here we might want to say that such an object
> (an A-label with upper ascii characters in it MUST not be
> registered).
>
> does that help? we already say something like that by
> definitions I think.
We say it by saying that nothing but [valid] A-labels can be
registered and that strings that cannot be obtained by
conversion from U-labels are not [valid] A-labels. ("valid" in
the previous sentence is completely redundant and added only for
emphasis.)
I suspect that, in light of this discussion, we may need to make
that more clear, but that we need do little else. I don't know
whether it would also be desirable to add specific language
permitting lower-casing of the strings; I'd like to see Lookup
explicitly banned from sending A-labels with upper case
characters off to the DNS.
john
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