The name server system of the internet is based on a hierarchical structure. Top-level domains (TLD) are divided as
- country code top-level domains (ccTLD)
- generic top-level domains (gTLD).
Country-code top-level domains include, for example, the Finnish .fi, the Swedish .se and the Estonian .ee. Generic top-level domains include, for example, the traditional .com, .net and .org as well as hundreds of new gTLDs, such as .xyz, .berlin, .website, .cafe and .ski.
ICANN (Internet Corporation for Assigned Names and Numbers) and IANA (Internet Assigned Numbers Authority) coordinate and
assign all top-level domains, ccTLDs and gTLDs to the operators.
Each top-level domain has an administrator. TLDs are usually administered by a private or public foundation or some other independent organisation. Each organisation administers the domains in accordance of their own legislation and agreements.
The Finnish .fi domain is administered by Traficom. Traficom maintains the fi-domain name register and ensures that websites and emails based on fi-domain names function 24/7 all over the world.