IDNA2008 doesn't require that validation be done on punycode. http://tools.ietf.org/html/rfc5891#section-5.3
If the input to this procedure appears to be an A-label (i.e., it starts in "xn--", interpreted case-insensitively), the lookup application *MAY* attempt to convert it to a U-label For IDNA2003, the processing is a bit murky. And some browsers check while others don't. UTS46, on the other hand, does require that a punycode label be validated, so in this it is more strict than IDNA2008: http://unicode.org/reports/tr46/#ProcessingStepConvertValidate Mark *— Il meglio è l’inimico del bene —* On Tue, Jun 28, 2011 at 19:41, Chris Weber <ch...@lookout.net> wrote: > The registrar http://cps-datensysteme.de has this domain name registered > and returns its own error page. I tried registering xn--fa-hia.de at > several registrars and received the error that the domain name was invalid, > not that it was taken, but that there was an error, or it was illegal > punycode. >
