Punycode & nslookup

Chris Buxton cbuxton at menandmice.com
Sun Dec 6 10:00:06 UTC 2009

On Dec 5, 2009, at 5:04 AM, Kai Szymanski wrote:

> What is the way for the future: Should the browser encode idn's into
> punycode and send it to the nameserver (like example below) or should
> the browser send the un-encoded idn to the nameserver and the nameserver
> have to do the "encoding-stuff" ? Or both ?

The theory, as JFC Morfin pointed out, is that applications are supposed to handle it. But most types of net-enabled applications don't - mainly just web browsers.

The most recent Windows stub resolver now handles the encoding on behalf of applications that don't do it themselves. This means that DNS servers (and firewalls) still don't need updates - the encoding is still handled by the client machine - but it also has the advantage that all applications get it automatically unless they deliberately try to validate hostnames using the pre-IDNA rules.

Unfortunately, I don't know of any other operating system stub resolver that does this.

Chris Buxton
Professional Services
Men & Mice

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