What Is A Web Server?

Just about every web surfer has heard the term web servers but most people don't actually know what they are! So what is a web server and why do you need a web server on a website?In a certain sense a spider is a web server but that is not what we have in mind in this article! Here we explain in simple terms what a web server is and we also explain why they are so vital for the correct functioning of a modern website.

The most common type of web server in use today is probably Apache. This is a software application that runs on physical hardware device (also confusingly called a server). So when somebody mentions a web server they are usually referring to both the hardware device and the software that is running on it. Lets see how Apache works in practice:

lets say that you type in the address of a BBC web page into your browser

what then happens is that your browser will send a page request to the BBC website

an Apache web server on the BBC web site will then intercept your page request (note that a web page address is like a house address)

if the page you requested exists then Apache will retrieve it and send it back to your browser

you then see the page that you requested appear in your browser as if by magic :-)

So Apache's job is to accept web page requests and respond by providing the pages back to the requester. If a page does not exist then you will receive an error message back. Almost everyone has seen this annoying "404 Not Found" message. Apache is not the only web server. There are many others but it is the most commonly used.

Another very useful function of a web server is to perform load balancing. If a website gets a lot of traffic the website architect will usually decide to have many physical servers that can share the load. In order to distribute the load a web server like Apache is typically used. One way that is done is using what is called a "round robin" approach. Apache will accept all incoming page requests and then distribute these to the other servers (usually called back-end servers) each in turn. This way the load is distributed amongst the backend servers.

So from this brief explanation you can see that web servers are an important part of the modern internet and that there main functions in life are to to serve web pages and provide load balancing to backend servers.