What Happens When You Type google.com?
When you type google.com and press Enter, five systems fire in sequence: DNS finds the server's IP, TCP opens a connection, TLS encrypts it, HTTP requests the page, and the browser renders the response. Interviewers ask this because each step is a networking topic in miniature.
Step 1 — DNS: name to IP address
The browser needs an IP address. It checks its own cache, then the OS cache, then asks the configured DNS resolver. On a miss, the resolver walks the hierarchy — root server → .com TLD server → Google's authoritative server — and returns the A/AAAA record, caching it per its TTL.
Step 2 — TCP: the three-way handshake
With an IP in hand, the browser opens a TCP connection to port 443: SYN → SYN-ACK → ACK (details in our handshake guide). Along the way the packet is routed hop by hop, each router doing a longest-prefix match in its routing table, with NAT translating your private address at the home router.
Step 3 — TLS: the encrypted channel
Because it's HTTPS, a TLS handshake runs inside the TCP connection: the server proves its identity with a certificate, both sides agree keys, and everything after travels encrypted.
Step 4 — HTTP: request and response
The browser sends GET / HTTP/2 with headers (host, cookies, encodings). Google's front-end returns a response — status 200, headers, and the HTML body (see HTTP explained).
Step 5 — rendering (and dozens more requests)
The browser parses HTML, discovers CSS/JS/images, and repeats this whole cycle for each — usually reusing the open connection. DNS answers, TCP connections and static assets are all cached so the second visit is far faster.
How to answer it in an interview
Structure beats detail. Name the five stages in one breath, then offer depth: "Happy to go deeper on any stage — DNS recursion, the TCP handshake, TLS, or routing." The interviewer will pick the one they care about; that's where the follow-ups come from.
Frequently asked questions
What is the first thing that happens when you type a URL?
The browser resolves the domain to an IP address via DNS — checking browser cache, OS cache, then the recursive resolver, which walks root, TLD and authoritative servers on a cache miss.
Which protocols are involved in loading a website?
DNS (name resolution), TCP (reliable connection), TLS (encryption), HTTP/HTTPS (the request itself), plus IP routing, ARP on the local segment and NAT at your router.
Why do interviewers ask this question?
It tests whether you can connect the whole stack end to end — one question touches DNS, TCP/IP, routing, security and application protocols, revealing the depth of your fundamentals.
Does the whole process repeat for every page asset?
Largely yes — each image, script or stylesheet is another HTTP request, though browsers reuse open TCP/TLS connections and caches to avoid repeating DNS and handshakes.
Related articles
Want hands-on training?
Learn this on real Cisco lab devices with placement support at Attila Technologies, Ahmedabad.