Domain Names are names in the format “www.somewebsite.com”, and are the names that are used to find a website on the internet.
The Very Short Version
Just as your home has an individual street address, your web site also needs to have an individual “internet address”. This “internet address” is known as the domain name. When a letter goes to 123 Main Street the post office knows where to deliver the letter. Similarly, when an internet address such as www.helpspa.com (a domain name) is typed into a web browser such as Internet Explorer or Firefox, it tells your computer what web site to display.
That’s the minimum you need to know. If you’d like to learn just a bit more, keep reading. The next paragraph will talk about the Domain Name System (DNS), which is the “Phone Book of the Internet”
What is DNS, and How Does DNS Work?
As the non-internet world has a phone book with a directory of names and addresses, the computer world has something similar: the Domain Name System (DNS). The “big picture” purpose of the DNS system is to serve as a “internet phone book” for computers, whose purpose is to help computers get to websites on the internet.
Notice that I used the phrase “get to websites” and I didn’t use the phrase “find websites”. The reason I chose the word “get” is because the DNS system works to help computers “find” other computers only in the sense that the DNS system asks the question “Where can I find the web server that is hosting the website, www.helpspa.com?. The DNS system has nothing to do with the word “find” in the sense of internet search, or search engine listings.
Every time a person or a company registers a domain name, information gets added into the DNS database (in the same way an entry gets added into the phone book when you add a new phone line). You can think of the master DNS database as a huge “internet phone book” or “internet street map” — this explanation is a large oversimplification, but the concept is the same. There are computers around the world that keep a “master copy” of this database (we wouldn’t want it stored in only one place, would we?) and there are even more computers that have copies as well. These other computers that store copies of the DNS database are called (surprise) DNS servers.
How Does it Work?
Recall that the internet is a collection of computers, and that web sites are stored on these computers all over the world (computers that store web sites are called “web servers”). When you type the name of a web site in your web browser (i.e. www.helpspa.com), your computer goes to the local DNS server (just accept that this happens), where your computer “looks up” the domain name (internet address) information for the site you want to find. Your computer is basically asking the DNS server, “What is the address of the web server that hosts the website www.helpspa.com”? Though a process we won’t get into here, your computer now knows the address or location of the web site you want to find, and then goes to that computer on the internet to get the web site you want to see.
The figure below illustrates this process (there are lots of steps missing but this is the big picture):