How do domain names work?

Domain names work by taking the domain name that you type into your browser (along with the "www" bit) or into your email program (with the "xxxx@" bit) and then go and find where that domain name resides to either serve you up a web page, or send an email to someone at that domain name.

When you buy a domain name, your details (name, company name, address, etc.) are recorded in the database along with the domain name, the date that you purchased the name and the date you will be due to pay a "renewal fee" for the domain name. Depending on how and through which company you bought the name initially, you will own the right to use the name for between 1 year and 10 years before you have to pay this renewal fee (each company has slightly different policies, so read the small print carefully when you register a domain name!)

"Register" was in bold for a reason: when you buy a domain name, it is said that you are "registering" it (since in fact all your details are being registered, or recorded, in the central database). This is why the companies that let you buy domain names are called "registrars".

Domain Name Servers

After your domain name has been "registered", the location of your web site and / or your email address post box are sent to "domain name servers" (or "name servers") throughout the world. The process takes up to 24 hours to distribute this information - and it's a one-off task.

You remember we talked about domain names being a substitute for IP addresses? Well, there has to be somewhere where a computer can go to find out what IP address is associated with a particular domain name, since computers use IP addresses to locate data around the Internet. This association information between domain names and IP addresses is stored on these name servers.

Each name server is responsible for maintaining the master record of the information associated with certain domain names.

A domain name record requires two name servers: a primary name server (also known as a domain name server, or DNS for short) and a secondary name server. Name servers are scattered all over the Internet - there are thousands of them - and each one passes on requests for information ("where's the web site?") until it reaches the primary name server, which replies ("it's over there... see, where that sign is pointing to") and maps the domain name to the IP address, letting your computer find the right web site or email post box.

If the primary name server is not accessible (broken, switched off, behind a slow connection, etc.) then the request for information will be sent to the secondary name server.

Most domain name registrars (companies selling domain names) will set up your new domain name on their name servers, at least until you want to "move" it somewhere else. If you move a domain name, you are basically transferring the right to maintain the association between that domain name and its IP address to a different name server. This is often necessary, for instance, when changing web hosting companies. Again, the technical support staff at your web hosting company should be able to help you on this issue in more detail.

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