David LeadbeaterNov 7, 2022

Fun with internationalised domains:
Mastodon appears to render some Emoji characters in domains (but not all, I haven't had a chance to dig into the code yet).

If you want to be doubly verified, add a DNS record for "xn--13h" which is the punycode for ☑️, then configure and use that as your URL. See my profile for an example.

(I haven't posted an introduction, but expect more DNS crazy and silliness, some past hits have included Wordle over DNS and Wikipedia over DNS.)

#punycode #idna #unicode #emoji #dns

Show threadalarigNov 7, 2022
@dgl Punnycode has been designed for the range up to 0x10FFFF of unicode, which covers only utf-8 encodable characters, not utf-16. ☑️ is composed of U+2611 and U+FE0F so it’s not supposed to work.
https://datatracker.ietf.org/doc/html/rfc3492#section-5
Show threadDavid Leadbeater

@alarig there's no need to involve UTF-16 in this and that isn't relevant here; it's just Unicode characters. The variation selector isn't encoded and is in fact dropped as part of nameprep (I can't find the normative reference right away, but https://datatracker.ietf.org/doc/html/draft-josefsson-idn-test-vectors-00#section-4.1 has a test vector for nameprep which confirms).

Quite likely something added the variation selector here, but it would be stripped on actually trying to visit that URL. It definitely does work!

Nov 7, 2022 at 6:50amWeb
Show threadDavid LeadbeaterNov 7, 2022
@alarig obviously the character may display as the emoji variant or not, macOS + Chrome seems to prefer the emoji variant. It doesn't really matter here as they both display a tick of some form.