“No internet” is a symptom shared by many unrelated failures. The fastest diagnosis checks the chain in order: client link, address configuration, default gateway, DNS, router WAN, modem/ONT state, provider path and the remote service. A test should tell you which layer still works.

Use scope as evidence

One device failing is different from every wired and wireless device failing. One website failing is different from every public IP being unreachable. Public IP reachability with broken domain names points toward DNS; a 169.254 address points toward local IPv4 configuration; a healthy gateway with a dead WAN points upstream.

Avoid destructive first steps

A factory reset can erase exactly the settings needed to restore service. Reboot only when it can answer a question, and reset only when documentation or clear evidence makes it necessary. Capture configuration and provider requirements first.

Diagnostic guides

Five observations that narrow most outages

Write down the client IP, default gateway, whether the gateway responds, whether a public IP is reachable, and whether a domain name resolves. Add the router WAN state and modem/ONT indicators. Those checks usually tell you whether to stay on the client/LAN or move upstream to the provider.

Preserve evidence before rebooting recurring faults

A reboot can restore service while erasing logs, session state, or timing clues. For intermittent problems, capture status first so the next outage can be compared instead of treated as a brand-new mystery.