Ever wondered what’s happening behind the scenes when you type something like example.com/phone into your browser and hit Enter? Let’s break it down:

🔹 Step 1: Entering the URL

Bob types a URL into the browser. A URL typically has four parts:

  • Scheme: http:// → tells the browser to use HTTP protocol
  • Domain: example.com → identifies the server
  • Path: /product/electric → specifies the resource location
  • Resource: phone → the exact item Bob wants to view

🔹 Step 2: DNS Lookup

The browser needs the IP address of the domain. It searches through:

  • Browser cache
  • OS cache
  • Local network cache
  • ISP cache

If the IP address isn't found, a recursive DNS lookup is triggered (we’ll dive deeper into this in another post).

🔹 Step 3: Establishing a TCP Connection

With the IP address in hand, the browser sets up a TCP connection to the server.

🔹 Step 4: Sending the HTTP Request

The browser sends a structured HTTP request asking for the /phone resource under the domain example.com.

🔹 Step 5: Receiving the HTTP Response

The server processes the request and sends back an HTTP response.

If successful (status code 200 OK), it includes the requested HTML content like:

Hello world

🔹 Step 6: Browser Renders the Page

Finally, the browser takes the HTML and renders the page so Bob can see and interact with it.

🔍 Key takeaway:

Typing a URL triggers a chain of networking and server events — from DNS lookups to TCP handshakes to rendering web pages — all in a blink of an eye!