simon at josefsson.org
Thu Jan 27 22:21:58 CET 2011
John C Klensin <klensin at jck.com> writes:
>>> Is there anything else in IDNA2008 that lower case labels?
> There is nothing at all in IDNA2008 that lower-cases labels,
> much less applying the Unicode case folding operation (which is
> quite controversial, especially as a character-replacement
> mapping algorithm).
>>> Further, I don't interpret the above to cause case conversion
>>> of the string looked up in DNS. I only interprete it as
>>> converting it to lower case for the purpose of comparing with
>>> the output from the Punycode output. It would be nice if
>>> someone could confirm or reject this interpretation as well.
> That interpretation is correct. Note also that conversion of
> "ß" (U+00DF/ Sharp S/ Eszett) to "ss" is not a lower case
> conversion operation (because U+00DF is already lower case. It
> results from a case-folding operation instead.
Thank you for confirmation. This resolves another ambiguity I had when
implementing this aspect.
More information about the Idna-update