A computer is connected to Wi-Fi but cannot open any website. How would you troubleshoot the problem step by step?
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I would troubleshoot from the device outward and use each result to isolate the failing layer. First confirm that the computer is associated with the intended Wi-Fi network and determine whether other devices on that network can access websites. Then verify that the computer has a valid IP address, default gateway, and DNS configuration. Test reachability to the local gateway, then test access to a known public IP address, and finally test DNS name resolution. If network and DNS tests are successful, investigate web-specific causes such as a captive portal, proxy, VPN, firewall or endpoint-security policy, and browser settings. If several devices are affected, focus on the access point, router/firewall, WAN connection, DNS service, or ISP rather than the individual computer.
1. Confirm the scope and Wi-Fi association
Check that the computer is connected to the correct SSID, has an adequate signal, and is not in airplane mode or otherwise disconnected. Also check whether another device on the same Wi-Fi can browse normally.
This immediately distinguishes a device-specific problem from a network-wide problem. A Wi-Fi connection only confirms association with the access point; it does not confirm usable IP connectivity or Internet access.
- Only one device fails: Prioritize that computer's network configuration, security controls, and applications.
- Multiple devices fail: Prioritize the access point, router/firewall, WAN connection, DNS service, or ISP.
2. Validate IP configuration and local connectivity
Inspect the assigned IP address, subnet mask or prefix, default gateway, and DNS servers. The address and gateway should be appropriate for the local network. On IPv4, a 169.254.x.x address commonly indicates that the device did not obtain an address through DHCP.
Test the local TCP/IP stack if needed, then test the default gateway. Failure to reach the gateway suggests a local-network issue, such as incorrect addressing, failed DHCP, Wi-Fi isolation, an access-point or router issue, or local filtering. A ping result alone is not conclusive because some devices block ICMP, so use other available connection tests where appropriate.
- No valid address or gateway: Reconnect to Wi-Fi, renew the address lease where supported, and check DHCP or static network settings.
- Gateway unreachable: Investigate the wireless link, local addressing, access-point configuration, and router availability.
3. Separate Internet routing from DNS
If the gateway is reachable, test connectivity to a known public IP address. Successful access to a public IP indicates that basic routing beyond the local network is likely working. Failure points toward the router, firewall, WAN link, or upstream provider.
Next, perform a DNS lookup for a domain name and verify that the configured DNS servers are reachable and returning results. If public-IP connectivity works but names do not resolve, DNS configuration or the DNS service is the likely fault domain. Use an alternative approved DNS resolver only if organizational policy permits it.
- Public IP works, names fail: Check DNS server settings, DNS reachability, and DNS filtering or outages.
- Public IP fails: Check the router or firewall, WAN status, upstream routing, and ISP service.
4. Check web-specific and application-specific causes
If IP connectivity and DNS resolution work but websites still do not open, check for a captive portal that requires sign-in, an incorrect proxy configuration, VPN behavior, firewall or endpoint-security restrictions, and browser extensions or browser security settings.
Try another browser or another Internet-enabled application. If only one browser fails, reset or correct that browser's settings. If all browsers and applications fail while network tests succeed, focus on system-wide proxy, VPN, security, or policy controls.
- Captive portal: Complete the required sign-in or accept the network terms.
- Proxy or VPN: Verify that the configured service is reachable and required settings are correct.
- Security controls: Review firewall, endpoint-security, and organizational web-filtering policies for blocks.