Fault-finding
Some websites will not open but others work
Almost always DNS rather than the connection. Test by opening a site by its IP address, or by switching one device to a public DNS resolver — if it starts working, your resolver was the problem. A whole connection failing looks completely different from selective sites failing.
Written and reviewed by our networks and fiber bench · Last reviewed
Selective failure is a naming problem
If some sites load and others do not, packets are clearly reaching the internet, so the connection is fine. What is failing is the translation from a name to an address. That narrows the diagnosis enormously and rules out everything to do with your router's connection, the ONT, or the ISP's line.
Test with a different resolver on one device
Change one device to a well-known public DNS resolver and try the failing site. If it loads, your ISP's resolver or your router's cache was at fault. Changing it on one device first rather than the whole network means you learn something instead of changing two variables at once.
Clear the caches, in both places
Both the operating system and the router cache DNS answers, including failed ones. A stale negative entry keeps a site unreachable long after the underlying problem has gone. Flushing the client cache and restarting the router clears both, and it is worth doing before concluding anything about the resolver.
Then consider filtering
Some sites are genuinely unreachable from Pakistan for reasons outside your network, and some are blocked by a firewall or content filter on your own equipment. If a site fails from every device and every resolver on your connection but works on mobile data, that is the distinction — and it is not a fault to fix.
Why do some websites not load while the internet works?
How do I know whether it is DNS?
Change one device to a public resolver and retry the failing site. If it loads, it was DNS. That single test takes a minute and it separates a naming problem from everything else, which is most of the diagnosis. Testing on mobile data as well tells you whether the site is reachable from Pakistan at all.
Should I change DNS for the whole network?
Often yes, and it is a small change on the router that applies to every device. A public resolver is frequently faster and more reliable than an ISP's. Test it on one device first so you know it actually helps before making it the default for everyone in the building.
The site works on mobile data but not on WiFi. What does that mean?
That the site is reachable and the problem is specific to your connection — usually DNS, occasionally a firewall rule or a content filter on your own router. Try a public resolver first. If that does not fix it, look at whatever filtering is configured on the router before assuming an outside cause.
Rather have it done?
This is the equipment the whole network depends on: a router that routes, a managed switch that can be diagnosed, and a firewall with rules someone wrote deliberately. A small-office set installed and configured runs PKR 45,000 to 150,000, sized to how many devices you actually run.
Router, switch and firewall setup in Islamabad — prices and scope