ietf-822
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Re: IDN (was Did anyone tell Microsoft yet?)

2002-04-26 19:52:31

If case-folding is done before encoding as in nameprep, then the comparison
will succeed.  If the case-folding is not done, then the comparison will
fail unless the two local-parts being compared are spelled with the same
casing - essentially forcing case-insensitivity.

Case-folding is easily done in ASCII, and even in ISO-8859-1, but there is
no way a mailer can do case folding in some strange part of Unicode that
it has never heard of (or which had not even been defined at the time that
mailer was compiled).

correct.  and IDNA doesn't do case-folding except for ASCII letters, for
consistency with the handling of ASCII-only DNS names.

Keith