prohibiting previously mapped and unmapped characters

Harald Alvestrand harald at
Wed Nov 29 22:51:33 CET 2006

--On 29. november 2006 16:19 -0500 Greg Aaron <gaaron at> wrote:

> Quantifying the scope of the issue is a good idea.  However, the number of
> live IDN Web sites is not the most pertinent metric, and it will not tell
> you which characters are never used.  More important is how many (and
> which) IDNs have been registered and are currently in domain name
> registries.

I do not agree.

In my opinion, current use of IDNs is likely to be mostly use of CNAMEs to 
point to websites that are also reachable by ASCII names - because no sane 
person would spend the effort to put content on the Internet that could 
*only* be reached by IDNs.

The harm to the Internet in making all those IDNs go stale would not be 
The harm to the Internet in making all the IDNs that aren't used yet go 
stale would be smaller.

> A significant percentage of domain names do not resolve.  In the various
> gTLDs, that percentage is 24% and up.  An even higher percentage of IDNs
> do not resolve, because IDNs are still catching on, and because Internet
> Explorer has not supported IDNs until very recently.  And even if a domain
> does not resolve, the registrant can activate it at any time.
> Also, the amount or type of content on a resolving domain is irrelevant.
> All domain names are equal in that they have been paid for, they may be
> used at the registrant's pleasure, and service has been promised by the
> registry and registrar during that domain's registered lifetime.  (To use
> an example from another industry with numerical identifiers: the phone
> company will not take away your phone number just because you haven't
> called anyone recently.)

I can see that if I regard the registry/registrar/registrant relationship 
as the most important part of the Internet. I don't.

And anyone who has lived through a change of numbering plan will fall over 
laughing at the idea that "the phone company will not take away your phone 

> Here is another way to approach the problem.  The number of published IDN
> tables is finite  < >.
> Which collide with the possible areas of backwards-incompatability?

That's a good idea in any case.

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