DNS (Domain Name System) is the internet's phone book. You type a name — google.com — and DNS looks up the real numeric IP address your computer uses to connect to that site. It's the step that turns a readable name into a routable address.

Why it matters for you

Most "website won't load" and "site can't be reached" problems are really DNS problems, not a dead site. Common ones:

  • DNS_PROBE_FINISHED_NXDOMAIN (Chrome) — the name couldn't be looked up at all.
  • A site loads but shows the wrong page or a "connection reset" — a bad or stale DNS entry.

Quick fixes

  • Flush your DNS — in Windows, run ipconfig /flushdns. Clears the local cache.
  • Use a public DNS — set your adapter to 8.8.8.8 (Google) or 1.1.1.1 (Cloudflare) instead of your ISP's. Reversible and standard.
  • Reboot the router — it clears the router's DNS cache too.

Is my ISP's DNS slow?

Sometimes. A public DNS like Cloudflare or Google is often faster and more reliable than the default your ISP hands out — and switching to it is a free, reversible experiment.

If only one or two sites fail while everything else works, it's usually that site's DNS (or a typo), not your connection.