fully-qualified domain names containing differently-encoded labels ?

Andrew Sullivan ajs at shinkuro.com
Mon Oct 25 22:31:11 CEST 2010

On Mon, Oct 25, 2010 at 01:23:45PM -0700, =JeffH wrote:

> But in any case, it would seem that any specification of conversion 
> operations on a multi-label domain name, that takes into account 
> IDNA{2003,2008}, needs to properly allow for and accomodate 
> label-by-label type diversity, yes?

Given that neither IDNA2008 nor IDNA2003 had anything to say about
domain names, but only about label names, I should hope so.  You
should treat them only by label, and not by domain name.  In general
in the DNS, this is true anyway.  You have no way of knowing whether
there are actually 8-bit-clean labels inside a domain.  They're
perfectly legal under STD13, but they violate the hostname rules.  If
you're not naming a host for hostname-compatible purposes, there is
nothing wrong with creating the label "punctuationmistake's" inside
your domain "example.com".

Moreover, note that your use of "type" there seems a little suspicious
to me.  If these were really different types in any important way, I
would have expected rather strong arguments in favour of changing the
xn-- prefix.


Andrew Sullivan
ajs at shinkuro.com
Shinkuro, Inc.

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