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For most people nowadays, using the internet involves accessing information or entertainment, viewing products and services, or using social media platforms to keep in touch with friends and family. It may seem that visiting a webpage merely involves entering the URL in the address bar, but that’s just the start of a more complicated process. In a split second the browser makes contact with globally distributed web servers, requests stored data packages, and then assembles the webpage from the information contained in the packages. Read on to find out how this process works and which steps are taken.
From URL to IP address
The easiest way to access a website is to write the desired address into the address bar located in the browser. This address is known as a Uniform Resource Locator (URL), and every webpage can be reached with its own individual URL (web address). A URL is made up of several sections; all of which have their own functions. Here is a generic example of a webpage URL:
The World Wide Web (WWW) is a system of electronically stored hypertext documents. The hypertext transfer protocol (HTTP) is used in the World Wide Web in order to transfer webpage data from the web server to the browser. In addition to HTTP, there’s also an encrypted version of the protocol: Hypertext Transfer Protocol Secure (HTTPS). The HTTP protocol header is followed by the hostname, which consists of a second-level and top-level domain (in this order). In the web, we usually see “www” as third-level domain, but there are other subdomains. If a URL points to a specific directory or file, the relevant information will be placed after the hostname.
URLs are generally comprised of letters, meaning that people can easily remember them. Computers, on the other hand, work with combinations of numbers (known as IP addresses) to find a server on the internet. An additional step is required in order to access content from the web browser. This step requires translating a webpage’s URL into the corresponding IP address. The task is carried out by DNS servers, which are responsible for managing the Domain Name System.
DNS server: a directory for IP addresses
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 as a link between computer and server
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.
Data exchange via HTTP
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.
Page rendering in web browsers