What happens when you hit “google.com” ?

When you enter "google.com" in your browser and hit Enter, several steps take place in the background to retrieve and display the Google homepage. Here's a step-by-step explanation

1. DNS Resolution

   • The browser first checks its cache to see if it already knows the IP address associated with "google.com." If it's not in the cache or the cache has expired, the browser initiates a Domain Name System (DNS) lookup.

   • The DNS server is responsible for translating the human-readable domain name (like "google.com") into an IP address. The browser sends a DNS query to a DNS server, often provided by your Internet Service Provider (ISP) or a public DNS service like Google's 8.8.8.8.

   • The DNS server responds with the IP address associated with "google.com."

2. Initiating a TCP Connection

   • The browser uses the obtained IP address to establish a Transmission Control Protocol (TCP) connection with Google's server. TCP is a reliable, connection-oriented protocol that ensures data integrity during transmission.

3. TLS Handshake (if using HTTPS)

   • If "google.com" uses HTTPS (which is likely the case), the browser and the server engage in a TLS (Transport Layer Security) handshake. This involves negotiating encryption parameters to establish a secure communication channel. This is crucial for protecting the data exchanged between the browser and the server.

4. HTTP Request

   • Once the connection is established, the browser sends an HTTP request to the server. This request contains information like the type of request (GET, POST, etc.), the resource being requested ("/" for the homepage), and additional headers.

5. Server Processing

   • Google's server receives the HTTP request and processes it. In the case of the homepage request, the server generates the HTML content for the Google homepage.

6. HTTP Response

   • The server sends back an HTTP response containing the requested HTML, along with any additional resources such as images, stylesheets, or scripts referenced in the HTML.

7. Rendering the Page

   • The browser receives the HTML and begins rendering the webpage. It parses the HTML to create the Document Object Model (DOM) and fetches additional resources as needed.

8. Page Display

   • The browser displays the fully rendered Google homepage on your screen.

Throughout this process, various protocols (DNS, TCP, TLS, HTTP) and standards come into play, ensuring a secure and efficient communication flow between your browser and Google's server.