looking up domain names with unassigned code points

John C Klensin klensin at jck.com
Sun May 11 21:10:49 CEST 2008

--On Sunday, 11 May, 2008 17:13 +0200 Cary Karp <ck at nic.museum>

> Quoting Vint:
>> technical question:
>> if someone generates an arbitrary  string of the form "xn--
>> <random   sequence of lowercase a-z, 0-9 and hyphen>
>> does the algorithm ALWAYS produce a sequence of UNICODE code
>> points?   Note I did not say a PVALID set of code points or
>> even ASSIGNED.
> I'm not sure if or how it weighs into the consideration of
> this question but on April 28th, the .SU TLD registry began
> accepting the registration of subdomain labels beginning with
> xn-- without requiring them to be valid output of the Punycode
> algorithm:
> "A user or service provider can either design software used for
> decoding and decoding algorithm on his own or use PUNYCODE
> algorithm recommended by ICANN and published in RFC documents."
> 	http://www.fid.su/english/?newsid=1207819620
> One purpose of allowing non-IDNA-compliant alternatives
> appears to be to permit script mixing:
> "In the process of generation of domain names with xn-- prefix
> using encoding algorithms mentioned in RFC documents
> registrators are not allowed to mix symbols of different
> national alphabets." 

Of course, there is no such requirement or restriction in either
IDNA2003 or proposed for IDNA2008, nor are there strong
guidelines that prohibit such registrations.  Some serious
confusion and/or FUD going on here.


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