The journey of a request: what happens when you open a website?
The most famous networking interview question: “what happens when you type a web address and press Enter?” The answer ties together everything so far. Step through it:
Layer: 7 · DHCPStep 1 of 7
1 · Get an address
The laptop joins Wi-Fi and asks for an address. The router's DHCP server hands it 192.168.1.23 and tells it the gateway (192.168.1.1) and the DNS server.
Notice that TCP starts with a “three-way handshake” (SYN → SYN-ACK → ACK) so both sides know the other is ready, then TLS agrees on an encryption key. That's why HTTPS shows a padlock.
| TCP | Guarantees all data arrives in order and resends what's lost. Used for websites, email and file transfer. |
| UDP | Sends fast with no confirmation. Used for video calls, gaming and live streams, where delay hurts more than a lost fragment. |
Watch outTools to see this yourself:
ping checks whether a host answers, tracert (or traceroute) shows every router on the way, and nslookup asks DNS about any name. Try them in a terminal.