Imagine you receive a call from a user who cannot connect to the internet. Walk me through how you would diagnose the issue.

Situation

In a hypothetical technical support call, a remote employee reports that their laptop suddenly cannot reach any websites or company resources, though they can log in normally. They are on a tight deadline and sound stressed.

Task

I need to methodically identify whether the issue is at the user's end, the local network, or beyond, and guide them to a resolution while keeping them reassured.

Action

I would begin at the physical layer: ask if the Ethernet cable is plugged in or if WiFi is enabled, and check for link lights. Then move to data link: verify the network adapter status and whether they have a valid IP address via ipconfig (if Windows). I'd ping 127.0.0.1 to confirm the TCP/IP stack works, then ping the default gateway to test local network connectivity. If that works, I'd ping 8.8.8.8 to see if external traffic reaches the internet. If local but not external, I'd check DNS by pinging a domain name versus an IP, and inspect proxy or firewall settings. I'd also ask them to try a different device on the same network to isolate the problem.

Result

By following this bottom-up OSI-model approach, I would isolate the fault in under ten minutes, whether it's a loose cable, DHCP misconfiguration, DNS outage, or ISP issue, and either resolve it or escalate with clear diagnostic notes.