What Happens When You Type “https://www.google.com” in Your Browser and Press Enter?

1. DNS Request:
   Before anything else, your browser needs to translate the human-readable URL, like “www.google.com," into an IP address understood by the internet. This translation is accomplished through a Domain Name System (DNS) request. The DNS server holds a directory of domain names and their corresponding IP addresses, allowing your browser to locate the appropriate server to retrieve the webpage.

2. TCP/IP:
   Once the DNS server provides the IP address, your browser initiates a Transmission Control Protocol (TCP) connection to the server hosting the website. TCP ensures reliable data transmission by breaking down the data into packets, which are then reassembled at the destination. Internet Protocol (IP) determines how these packets are routed across the network to reach the server.

3. Firewall:
   As the packets traverse the internet, they may encounter firewalls, which act as security barriers to filter and monitor incoming and outgoing traffic. Firewalls enforce predefined rules to permit or block data packets based on factors like source IP, destination IP, and port numbers. This ensures that only legitimate traffic reaches the web server.

4. HTTPS/SSL:
   In the era of heightened cybersecurity concerns, the Hypertext Transfer Protocol Secure (HTTPS) protocol plays a vital role in safeguarding data exchanged between your browser and the web server. HTTPS encrypts the data using Secure Sockets Layer (SSL) or Transport Layer Security (TLS), preventing unauthorized access or tampering during transit.

5. Load-Balancer:
   Websites with high traffic volumes often employ multiple servers to distribute the load and ensure optimal performance. A load balancer sits between the client and the server farm, distributing incoming requests across various servers based on factors like server health, current load, or predefined algorithms. This ensures efficient resource utilization and enhances scalability.

6. Web Server:
   Upon reaching the designated web server, the HTTP request is processed, and the corresponding webpage is fetched from the server’s storage. The web server, such as Apache or Nginx, handles this request, retrieves the necessary files, executes any server-side scripts (if applicable), and generates the HTML content to be sent back to the client.

7. Application Server:
   In cases where dynamic content or server-side processing is involved, an application server comes into play. Application servers, like Node.js or Django, execute the server-side logic, interact with databases, and generate dynamic content based on the user’s request. This allows for personalized and interactive web experiences.

8. Database:
   For websites requiring persistent data storage, databases serve as the backend repository for storing and retrieving information. When a webpage requires data from a database, the application server communicates with the database server, executes queries, and fetches the relevant data to be displayed on the webpage.

Conclusion:
In conclusion, the journey of a URL from the browser’s address bar to the fully rendered webpage involves a complex orchestration of various components within the web stack.

By understanding each component’s role, from DNS resolution to database interaction, software engineers can gain insights into the underlying mechanisms driving web applications, empowering them to tackle interview questions with confidence and excel in their roles.