Distributed configuration of "private" IDNA (Re: IDNA and getnameinfo() and getaddrinfo())

[Andrew Sullivan]

On Thu, Jun 17, 2010 at 11:30:38PM +0000, Shawn Steele wrote:
> I cannot imagine why you'd want to force a Unicode string to punycode to pass it between applications, unless you are doing a DNS query.  The canonical form should be U-label and that's what apps should exchange.
> 

It seems to me that if you're going to require the exchange of only
U-labels, and you're going to validate your input, then it actually
doesn't matter whether you exchange U-labels or A-labels: they're
freely convertible back and forth, and if you want to know whether
something is a valid U-label (for instance), the easiest way might
well be just to convert it to an A-label, and back into a U-label, and
see if you get the binary equivalent as output.

So an application that expects to hand around DNS label slots as
U-labels actually needs to be able to cope with A-labels, and
conversely, it seems to me.

A

-- 
Andrew Sullivan
ajs at shinkuro.com
Shinkuro, Inc.