Senior

What happens after entering google.com in the browser and pressing Enter? Describe the entire process and participants.

sobes.tech AI

Answer from AI

When a user enters the address google.com in the browser and presses Enter, the following process occurs:

Browser cache check — the browser checks if there is already a saved response for google.com in the local cache.
DNS query — if the cache is empty, the browser sends a request to the DNS server to obtain the IP address corresponding to the google.com domain. This may involve several steps: request to the local DNS, then to root servers, top-level domain servers, and authoritative DNS.
Establishing TCP connection — after obtaining the IP, the browser establishes a TCP connection with the server on port 443 (if HTTPS) or 80 (HTTP).
TLS handshake (if HTTPS) — exchange of certificates and establishment of a secure channel.
Sending HTTP request — the browser sends an HTTP GET request to the server.
Server processes the request — the Google server receives the request, processes it, and generates a response (HTML, CSS, JS, etc.).
Receiving and rendering the response — the browser receives the response, starts parsing HTML, and loads additional resources (scripts, styles, images).
Displaying the page to the user.

Participants in the process:

This process involves interaction at different levels of the network model — from DNS (application) to TCP/IP (transport and network).