Why do Cyrillic letter in URL domain appears so strange?

Question

Short explanation:

Why does russian characters in domain name in URL перезагрузкаопмо.рф get mapped to some randomness like this: http://xn--80aaigamcyttbbjfe2c.xn--p1ai. Please note, I am not speaking about the issue with decoing in URL like this one: http://ru.wikipedia.org/wiki/%D0%97%D0%B0%D0%B3%D0%BB%D0%B0%D0%B2%D0%BD%D0%B0%D1%8F_%D1%81%D1%82%D1%80%D0%B0%D0%BD%D0%B8%D1%86%D0%B0

Long explanation:

I was looking into the list of sites that has problems with the recent heartbleed exploit, and the site with a strange domain name surprised me: http://xn--80aaigamcyttbbjfe2c.xn--p1ai/. In any other case I would assume that this is porn/viagra/exploit/dyingNigerianPriceSendingMoney kind of site (based on it's cryptic name), but global ranking of 46000 is impossible for this kind of things.

Looking into the site, it looks like it is in russian, and based google translation - it is about politics. But who will go to this site with such url? When I investigated it a little bit further, I found that it actually has normal url like this (перезагрузкаопмо.рф/‎). But when I enter this into my address bar it changes it to the previous url.

So what is the problem here? Why does перезагрузкаопмо.рф/‎ maps to http://xn--80aaigamcyttbbjfe2c.xn--p1ai/.

Solution

So what is the problem here? Why does перезагрузкаопмо.рф/‎ maps to http://xn--80aaigamcyttbbjfe2c.xn--p1ai/.

DNS is old, and historically has only supported the 26 Latin characters A through Z and the dash. I suppose the original designers of DNS didn't think it would last long enough to be used internationally or something like that.

However, of course the Internet is international, so domain names ought to be international as well.

The http://xn--80aaigamcyttbbjfe2c.xn--p1ai/ is actually an encoding system called Punycode - it's a way of representing a domain name with a non-DNS character set within the DNS character set. These domains are called Internationalized domain names (IDNs).

Most recent browsers will display IDNs in the native character set, if configured to do so. The Punycode is what gets sent to the DNS server behind the scenes. You should update your browser or check your settings if IDNs aren't showing up in your browser.

I was under that above impression, but after reading this it seems that to protect against domain phishing using characters that look similar, algorithms or whitelists are applied to determine which IDNs are displayed as native characters or as the punycode.

Part of that algorithm for Chrome is your current language setting.

When I went the Chrome's settings, down to Language and Input settings, and added Russian, and selected it, the http://xn--80aaigamcyttbbjfe2c.xn--p1ai showed up as перезагрузкаопмо.рф in the browser.

Comments

[Devid]

I copy pasted the url you posted, and no problem with me, the url opened and the name did not change. I use chrome.

[Salvador Dali]

So you posted перезагрузкаопмо.рф in address bar and it still looks the same? In my case it is http://xn--80aaigamcyttbbjfe2c.xn--p1ai

[Devid]

Here is a interesting article and why you see the punycode showing: uxmag.com/articles/a-url-in-any-language

[Salvador Dali]

Cool explanation, but what I find strange is Most recent browsers will display IDNs in the native character set. I am using the latest chrome, so this is strange for me.

[LawrenceC]

See edits. I looked into this a bit more.

[Gerald]

I wrote a bit about this on h2g2.