What happens when you type google.com in your browser and press Enter
As we browse the web, we often take for granted the intricate process that happens behind the scenes when we type a URL like https://www.google.com and hit Enter. In this blog post, we’ll dive deep into each step of this journey to understand how our browsers communicate with servers and deliver web content seamlessly.
DNS Request:
The journey begins with a Domain Name System (DNS) request. When we type “https://www.google.com" in our browser, our computer sends a DNS query to a DNS resolver to translate the domain name (www.google.com) into an IP address. The resolver checks its cache; if the IP isn’t cached, it queries authoritative DNS servers until it finds the correct IP address.
TCP/IP:
Once we have the IP address of the server hosting www.google.com, our computer establishes a Transmission Control Protocol (TCP) connection using Internet Protocol (IP). TCP ensures reliable data delivery by breaking information into packets, sending them, and reassembling them at the destination.
Firewall:
Before the TCP handshake completes, the request may pass through a firewall. Firewalls act as a barrier between our computer and external networks, enforcing security policies to allow or block traffic based on predefined rules.
HTTPS/SSL:
Now, the magic of HTTPS (Hypertext Transfer Protocol Secure) comes into play, ensuring that our communication with the server is encrypted. The SSL/TLS (Secure Sockets Layer/Transport Layer Security) protocol secures the data exchanged between our browser and the server, protecting it from eavesdroppers and ensuring authenticity.
Load-Balancer:
For high-traffic websites like Google, a load balancer sits between the client and multiple web servers. It distributes incoming requests across these servers, optimizing performance, maximizing uptime, and preventing any one server from becoming overwhelmed.
Web Server:
Once the load balancer selects a web server, the server processes our HTTPS request. It retrieves the requested webpage and any associated resources (images, scripts, stylesheets) from storage and prepares them for delivery.
Application Server:
In more complex web applications, an application server may be involved. It executes dynamic code, interacts with databases, and generates content tailored to the user’s request. This step is crucial for interactive and data-driven websites.
Database:
If our request requires data retrieval or modification, the application server communicates with a database server. The database stores and manages structured data, such as user accounts, search results, or product information, ensuring data integrity and availability.
Finally, after all these steps, the web server sends the assembled webpage and resources back to our browser over the established secure TCP connection. Our browser receives the content, interprets HTML, CSS, and JavaScript, and renders the webpage, completing the journey from typing a URL to viewing a fully functional web page.
Understanding this journey gives us a profound appreciation for the complex infrastructure and protocols that underpin our everyday web browsing experiences. It also highlights the collaboration between various components, from DNS and networking to security measures and server-side processing, to deliver seamless web interactions.