National Domains

Encodes and decodes national domain names, for example:
www.yandex.rf
to
www.%D1%8F%D0%BD%D0%B4%D0%B5%D0%BA%D1%81.%D1%80%D1%84
or backward.

https://www.eurodns.com

Registrar of European domains.
www.asiadns.com - registrar of Asian domains.

National Domains only 243, According to the number of 2-letter codes of countries and territories in accordance with the international standard ISO 3166-1

Domain .TV was used as an international one.
the Head of the country has concluded the corresponding contract with the Canadian businessman.
However, domain ownership remains for the country.

Domain registration

1. Closed registration, only for citizens are strange.

2. Open Registration, for all comers, only pay.

This was the country of Great Britain. Now in the UK, the registration of domains of the 1st level is open.
But if you have a domain in the .CO.UK zone, the corresponding domain name is stored for free in the .UK zone.

If you do not use the 1st-level domain reserved for you for 5 years, It can be registered by anyone.

Special Registration

Registration of 2-character domains.
Not every country allows you to buy a 2-character domain.
If they allow you to buy, it's very expensive.
So only leading portals can buy, like

1. VK - www.VK.com
2. Classmates - www.OK.ru
3. Yandex - www.YA.ru
4. Mail.ru - www.MY.com

However, it is better to come up with a unique name, create a new word, like Google, Yahu or Yandex.