Re: djbdns and idn

On Wed, 25 Mar 2009, Bernd Plagge wrote:

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> as you may be aware idn (international domain names) are becoming reality.
> As such a first customer registered some Japanese domain names like
> 
> xn--gckjq7bzpybc7891dsu6b.net (IDNA code)
> 
> I understand that the domain name must be specified like 'xn--gckjq7bzpybc7891dsu6b.net' in djbdns.

Yes. That's what it looks like.

> What I would like to confirm is which software makes the translation
> from the national version (Japanese) to the IDNA code. Am I right to
> assume that the browser, mail program etc will be passing a converted
> domain string to djbdns? Or do we need a filter before and after
> djbdns doing this translation?

The DNS software, doesn't make this translation. It's done by your
client.  IDNA will work transparently on every 8bit clean DNS server or
resolver.

You have no worries so far as DNS is concerned, //except// that IDNA
makes domain names longer than they may seem (multiple bytes per
international character), and so one may run into the 63 byte label or
255 byte total length limits in DNS.  

Your example of xn--gckjq7bzpybc7891dsu6b.net name encodes 9 characters
(without ".net") but is a 25 character DNS label.

Other than that, everything is completely transparent to DNS.  Though
sorting by DNS name might produce unexpected results.

		--Dean



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