User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:40.0) Gecko/20100101 Firefox/40.0 Build ID: 20150807085045 Steps to reproduce: Click on this link http://・ω・.blargel.com Actual results: The following message appears: Server not found Firefox can't find the server at %e3%83%bb%cf%89%e3%83%bb.blargel.com. Firefox appears to encoding the IDN subdomain strangely before trying to resolve it. Expected results: Firefox should convert the subdomain into punycode instead of whatever it's doing above so that it resolves properly and the page loads.

Hmm strange... It works if you click on the link from here. It definitely fails if you try to click on the face in the README on this git repo. https://github.com/Blargel/shopoon

This actually seems like an issue with how Github is rendering the link. Regardless, Chrome handles this case perfectly fine.

Gijs, any idea who would know about an issue like this? It seems like Firefox is able to navigate to an IDN host if a link uses the "pretty" version: <a href="http://・ω・.blargel.com/"> but it fails if the link uses the encoded version: <a href="http://%e3%83%bb%cf%89%e3%83%bb.blargel.com/"> Chrome Canary is able to navigate via either form of the link.

Valentin or Anne van Kesteren.