We already mentioned the "central database" for domain names. This central database is stored on several different computers, spread out all over the world. The company InterNIC maintains this central database.

When you buy a domain name, your data (name, company name, address, etc...) are registered in the central database , along with the domain name itself, purchase date and expiry date (= date when you have to renew your rights). Depending on how and via which company you originally bought the domain name, you own the rights for a period from 1 to 10 years. When this period has expired, you need to pay for renewal of the rights. Each company applies another policy, so don't forget to read the small print when registering a domain name!

"Registration" is not written in bold without a reason. When you buy a domain name, you "register" it (i.e. your data is being registered/stored in the central database). Therefore, companies where you can buy domain names are called "registration companies" or registrars.

When you register a domain name, you will receive an information request about the name servers you are going to use.

Do you remember that we talked about domain names replacing IP-addresses? Well, somewhere, a computer has to find out which IP-address is connected to which domain name (as computers use IP-addresses in order to find information on the internet). The information about the link between domain names and IP-addresses is stored on a name server (= domain name server).

A website can be compared with a shop, far away from the main road and hidden behind trees. You will need an indicator in order to find the shop. A domain name can be compared with this indicator; the IP-address is the direction in which the indicator points. When hired workmen - who have to place the indicator - don't know where the shop is located, they might place the indicator in the wrong direction. Therefore, it seems like domain names are useless: there is no IP-address linked to them.

Name servers can be compared with foremen, who give the workmen instructions about the indicator's direction. Once an indicator has been placed, it's direction can not be changed anymore, unless the workmen get new instructions. Each name server maintains the main information record, linked to certain domain names.

A domain name record requires two name servers: a primary domain name server (also known as domain name server or DNS in short) and a secundary domain name server. Name servers are spread throughout the internet: there are thousands of them. Every single one of them sends out information requests ("Where can I find the shop?"), untill it reaches the primary name server, who can answer the question ("It's over here, look at the indicator's direction"). The domain name is linked to the IP-address. This way, your computer can find the right website. If the primary name server is unavailable (broken down, turned off, slow connection, etc...), the information request will be sent to the secundary name server.

In reality, things are a bit more complicated than described above. Example: many name servers 'cache' information about frequently asked translations/linking/mapping between domain names and IP-addresses (cache = storage of information locally to be used again at later requests). When you change information about a certain domain name (e.g. changing the IP-address), it might take a couple of days before people can find your site at the new address (because the cached information on the local name server is not up-to-date anymore it might take a while to update it). This principle is called announcing new domain information.

Most domain name registration companies (i.e. companies that sell domain names) will install your new domain name at their name servers, at least untill you are planning to "transfer" it. When you transfer a domain name, you transfer the linking right between the domain name and its IP-address to another name server. This is often required, e.g. when switching to a new webhosting company. Again, your webhosting company's technical support will be glad to help you herewith.