[dns-operations] Emoji "Female" symbol fails to resolve at Google's 8.8.8.8 & 8.8.4.4

[Stephane Bortzmeyer]

On Wed, Jul 12, 2017 at 02:31:02PM +0100,
 James Stevens <James.Stevens at jrcs.co.uk> wrote 
 a message of 54 lines which said:

> He had tried quite a few different public resolvers who all seemed
> to work fine, like OpenDNS - not quite sure why they weren't also
> failing like Google.

Because they don't validate. Today, most resolvers (public or not)
don't validate.

> So you could argue that a resolver that is "fully IDNA2008
> compliant" might block an emoji domain name?

It is questionable wether this blocking should take place in the
resolver, or in the application on the user machine (or nowhere: be
liberal, etc).

> I can sympathise with ICANN not wanting them in the ROOT, but they
> seem pretty harmless at the second level - especially as Egyptian
> Hieroglyphs are allowed.

The ship has sailed, it is RFC 5892 (*not* ICANN).

> However, it would be easy for browsers to warn users if the URL is
> made from a mixture of different character sets

Very bad idea (in many countries, mixing scripts is common, read a
russian or japanese magazine on computing, to see many examples).