Stringprep Profile for Internationalized Domain Names (RFC 3491)http://search.cpan.org/dist/Net-IDN-Nameprep/
This module implements the nameprep specification, which describes how to
prepare internationalized domain name (IDN) labels in order to increase the
likelihood that name input and name comparison work in ways that make sense for
typical users throughout the world. Nameprep is a profile of the stringprep
protocol and is used as part of a suite of on-the-wire protocols for
internationalizing the Domain Name System (DNS).