In everyday language, people often do not distinguish between the internet and the WWW (World Wide Web), even though the two terms do not actually mean the same thing. The internet is a global system of interconnected networks, while the WWW can be understood as a service that runs on the internet. This service provides access to a huge amount of data, usually stored on web servers and typically accessed through a web browser. Opening a web page usually happens by typing the page’s URL into the address bar or by clicking on a link. Browsers then follow the rules of the DNS (Domain Name System) to find the required IP address and display the page.
First, browsers translate the URL into an IP address using DNS. In this process they receive a sequence of numbers, which represents the IP address associated with the domain. For example, the rackhost.hu domain corresponds to the IP address 91.227.139.38. The browser then sends an HTTP request over the internet to the computer associated with that IP address. The request is delivered according to the TCP/IP protocol, allowing the receiving computer to distinguish between different types of requests, such as HTTP requests or emails. The HTTP protocol typically uses port 80. The receiving computer then forwards the request to a web server. If the web server can fulfil the request, it sends an HTTP response back to the browser containing the requested page’s content in HTML format. The browser then interprets the HTML and displays the content.
The Map of the WWW
Most websites are connected to other pages, documents and downloadable elements through links. The collection created by these interconnected links is called an information network. This enormous network was named the World Wide Web, although the abbreviated form WWW eventually became more widely used in everyday language. The network can be represented using graphs, where the nodes represent different web pages and the edges represent the links between them.
The use of “www” in domain names refers to the services provided by servers. For example, a web server’s name often contains “www”, while an FTP server typically contains “ftp”. Today, however, the “www” prefix is increasingly omitted, as web servers are usually configured so that the domain name without “www” also points to the same website. Most well-known online services are typically used without the prefix as well, such as facebook.com, twitter.com or gmail.com.
The http:// or https:// found at the beginning of a web address indicates the use of the HTTP protocol. Unlike “www”, it plays an important role in accessing websites, as it determines the type of protocol used for requests and responses. Browsers usually add this prefix automatically when accessing a website.