This is another enormous subject which you only really need to understand small parts of.
Mostly, you will only need to know this when you start to think about how to get your site on the Web.
Domain names
Each Web site will normally have its own domain name. This one is on yourwebskills.com. Your browser should be displaying http://www.yourwebskills.com towards the top of the window. The www is just the name of my server in my domain. It could also be called fred but it isn't! Often you can leave out the www and the browser will still get you there because of the way servers handle a URL (e.g. http://yourwebskills.com) without the server/host name included. Other sites will actually make use of the chance to have many different servers attached to the same domain name (e.g. support.microsoft.com)
You may have noticed that domain names end in a variety of ways some of which look a like file name extensions. Each is supposed to have its own purpose. For example:
- .com is for international commercial Web sites
- .co.uk is for the same thing but aimed just at the UK
- .net is for network sites (like ISPs)
- .org is for non-profit organisations
- .me and .me.uk are for individuals or families
Not everyone follows these guidelines though. Some .COM domains are used just because the Web developer thinks that most people will assume that a site has .com at the end. They think that their site would get more visits using .com than .org (even if .org is the proper choice according to Web standards). Like this site.
You can get a domain name of your own from many registrars and resellers. They will also tell you if the domain is available. One.com and Easily are just two of the many. Prices start from almost nothing. You can pay to use the domain for a year or two and have the right to renew it each time. There is a big market in buying and selling domains names which might become popular.
IP addresses
Without getting into networking too much it is hard to explain this properly. Think of them like telephone numbers. Part of them (like the area code) points to a network (remember the Internet is made up of lots of different networks) and part points to a particular system (like an individual 'phone) on that network (a host which might be a server).
Your computer needs an IP address to access the Internet. You can search the Web for sites which will tell you your current IP address (the IP address you use on the Internet may not be the one your system uses for other purposes).
When accessing the Web a user will type the domain name and server name (e.g. www.yourwebskills.com). A server on the Internet will then convert that to an IP address so that the requests can be sent to the correct server. This server (a domain name server or DNS) is essential unless you type the IP address in manually to your browser (which you can do).
In summary the domain name is like a person's name and the IP address is like their telephone number. First you look up their number in a 'phone book (the DNS) and then you (your browser does it for you) dial to talk.
Static and dynamic IP addresses
A server will have a fixed (static) IP address. This means that the DNS knows where it is at all times. In contrast your home Internet connection will probably give you a variable (dynamic) IP address. The IP address may change every time you connect to the Internet.
This makes hosting a Web site at home difficult as the DNS will need to be told of the new IP address each time. Due to the way the DNS system works it could take hours for this change to be noticed by everyone (maybe days) and meanwhile your site is not accessible to everyone. There are ways around this but they have their problems.
