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alex / what-happens-when

An attempt to answer the age old interview question "What happens when you type google.com into your browser and press enter?"
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What happens when you type google.com in your browser and press Enter #2042

Open Zeshaninsta opened 2 months ago

Zeshaninsta commented 2 months ago

Have you ever wondered what really goes on behind the scenes when you type a simple URL like https://www.google.com into your browser and hit Enter? It might seem like a straightforward process, but under the hood, there's a complex ballet of technologies working seamlessly to deliver the webpage to your screen. Let's take a journey through the layers of this process.

  1. DNS Request: The journey begins with a Domain Name System (DNS) request. Your browser needs to find the IP address associated with the domain name www.google.com. It sends a DNS query to a DNS server, which then looks up the IP address and returns it to your browser.

  2. TCP/IP: Once your browser knows the IP address, it initiates a Transmission Control Protocol (TCP) connection to the server at that IP address. TCP ensures reliable communication by breaking data into packets and ensuring they arrive in the correct order.

  3. Firewall: As the TCP connection is established, it might encounter a firewall. Firewalls are security measures that monitor and control incoming and outgoing network traffic based on predetermined security rules. If everything checks out, the connection proceeds.

  4. HTTPS/SSL: Now comes the crucial step of securing the connection. In the case of Google, the URL begins with "https," indicating that it’s using Hypertext Transfer Protocol Secure (HTTPS). This means that data exchanged between your browser and Google’s servers is encrypted using Secure Sockets Layer (SSL) or Transport Layer Security (TLS) protocols, ensuring confidentiality and integrity.

  5. Load-Balancer: Google serves millions of users simultaneously, so it employs load balancers to distribute incoming traffic across multiple servers. This ensures that no single server becomes overwhelmed and helps maintain high availability and performance.

  6. Web Server: Once the request reaches Google’s servers, it is directed to one of many web servers. The web server’s job is to handle HTTP requests, process them, and return the appropriate HTML, CSS, and JavaScript files to the client (your browser) for rendering.

  7. Application Server: In the case of Google, there’s more to it than just serving static web pages. Behind the scenes, there are sophisticated applications running to handle search queries, display personalized content, and much more. These tasks are handled by application servers, which execute the necessary logic and communicate with databases and other services.

  8. Database: Behind every dynamic website like Google, there’s a database storing and retrieving data. Whether it’s user information, search indexes, or other data, databases play a crucial role in delivering the right content to the user. Application servers interact with databases to fetch or store the required information.

In summary, typing https://www.google.com into your browser triggers a complex chain of events involving DNS resolution, network protocols, security measures, load balancing, server-side processing, and data storage. Yet, thanks to the seamless integration of these technologies, you're able to access the desired webpage within seconds, often taking this intricate process for granted.

Zeshaninsta commented 2 months ago

What happens when you type google.com