How to access websites

When a web address is entered into the search bar of the browser, the browser looks for the requested domain in its cache. If it’s not there, it requests the operating system’s DNS server to find the required IP address. A DNS server is liable for the name resolution. The DNS server that is to be requested can be configured in the operating system as well as in the router. Per default, the internet access provider sets the address of its own DNS server there. Since requesting the domain name system takes some time, the IP addresses of sites that have already been visited are usually stored in the operating system’s or the browser’s DNS cache. This cache keeps IP addresses at hand for future visits to the website. This lightens the load of the DNS server and speeds up the webpage’s loading time.

The router is the interface between the internet and home network. It requests data from the internet and distributes it to networking devices such as desktop computers, laptops, and tablets. The router is required as a link since the devices in the home network communicate with each other using local IP addresses, while outwardly sharing the router’s public IP address. The network addresses are then translated with a process known as Network Address Translation (NAT). With modern IPv6 internet connections, translations via NAT generally aren’t needed since every device in the network is allocated a public IP address.

When the IP address of the chosen webpage is identified, the browser requests the relevant data for the page from the appropriate web server. This request takes place via HTTP in the form of a data packet, which contains all the information the web server needs in order to deliver the webpage data. The browser communicates the IP address of the chosen webpage, and provides information on the operating system, itself, and the device on which the webpage should be displayed. The router adds its own public IP address as sender and forwards the packet to the public internet. The web server processes the information and transmits an HTTP status code. Should the request be successful, the server sends a data packet to the web browser with all the information required for the page. If the server can’t find the webpage at the requested address, it either sends a 404 error code (webpage not found) or sends the visitor to the new URL via redirect if it’s known.

Incoming data packets from the internet are finally forwarded from the router to the computer on which the webpage is being accessed. The web browser then takes on the task of analyzing the data packets. Webpages generally comprise of HTML,CSS, and JavaScript files, whose lines of code contain detailed information about how the webpage should be presented. While HTML documents define the structure and controls of a webpage, the design information is specified in Cascading Style Sheets (CSS files). Elements that help user interaction on the webpage are usually implemented with JavaScript. The rendering engine of the web browser determines how the code is interpreted. Webpages can have a different appearance depending on the web browser used. Each browser has a cache in which data is temporarily stored when a webpage is accessed. This means that, when a webpage is re-visited, not all the data needs to be requested from the web server. The web browser simply retrieves the files that have changed since the last visit meaning that the website doesn’t take as long to access.