Internet
The Internet is a worldwide network of interlinked computers. Every time someone switches on their computer to read an email or search for a website they become part of this network of computers.
When someone accesses the Internet all they are doing is sending and receiving information between computers. Certain computers are left permentantly switched on to enable continuous access to the information they hold. These computers are called servers. A computer that asks for information from a server is called a client.
If you view a website, you are requesting the files associated with that website to be temporarily downloaded, from the server holding the files to your computer. In other words, you are acting as a client to the web server. The web server 'hosts' the website. The World Wide Web is the name given to the collection of web servers on the Internet that provide websites for people to look at. Whereas, the Internet contains not only web servers but also many other types of servers, for example mail servers.
Each computer on the network is given an address called an IP address, think of it like a telephone number. When a computer 'talks' with another computer it uses the IP address. If you know the IP address for the computer you wished to contact, you can simply type the IP address into the browser address bar. However, for humans a long series of numbers is difficult to remember, so instead we use letters to make up a word(s), called the domain name. The Domain Name System (DNS) converts the word(s) into the correct IP address. Similar to the address book on your mobile phone. For example, you select Fred in your mobile phone address book and press the call button on the phone; the phone will then call his telephone number. Just like the address book, the Internet contains servers that hold all the domain names. There is a degree of organisation in the structre of domain names. The top level domain is the .com or .co.uk bit, the next level is the company domain name. No combination of company domain name and top level domain can be the same, otherwise you would not know which website you would end up viewing!
When you view a website, you type in an address such as HTTP:\\www.rightmark.co.uk, this is the URL. This can be broken down into its components:
HTTP:// - defines the protocol used to transfer web pages from the web server to the client. www - is the server name, nearly all web servers use www rightmark is the company domain name .co.uk - is the top level domain.
To summarise, for people to view your website you must have:
- A unique website address. This a combination of your domain name with the top level domain
- The domain name must be registered on the DNS servers and it must be pointing to the location of the server containing your website.
- Your website must be located on a computer that is capable of receiving and sending requests through HTTP
- The server must be permanently connected to the Internet, unless you wish clients to see a 'Server not Found' message!
