DNS problems have a very specific fingerprint: you can ping an IP address directly, but visiting a website by name fails. That distinction is the fastest way to confirm DNS is the actual culprit before spending time elsewhere.
DNS (Domain Name System) translates human-readable names like example.com into the IP addresses computers actually use to connect — so a working internet connection can still fail to load websites if DNS resolution breaks.
Common Symptoms
- Browser shows “DNS_PROBE_FINISHED_NXDOMAIN” or “server not found”
- You can reach some websites (often ones you visited recently) but not others
- ping 8.8.8.8 works but ping google.com fails
- Problem clears temporarily after a reboot, then returns
Possible Causes
- Stale or corrupted local DNS cache
- ISP DNS servers experiencing an outage
- A manually configured DNS server address that’s no longer valid
- A VPN client redirecting DNS queries incorrectly
Before You Begin
Confirm it’s DNS and not general connectivity: open Command Prompt and ping 8.8.8.8. If that works but ping google.com fails, you’ve confirmed the problem is DNS specifically.
Method 1 — Flush the DNS cache
Open an elevated Command Prompt
Right-click Start → Terminal (Admin).
Flush the cache
Run the flush command shown in Useful Commands below, then retest a few websites.
Method 2 — Switch to a public DNS provider
Open adapter properties
Settings → Network & Internet → your connection → Edit DNS server assignment.
Set to manual
Switch to Manual, enable IPv4, and enter 8.8.8.8 and 8.8.4.4 (Google) or 1.1.1.1 and 1.0.0.1 (Cloudflare).
Method 3 — Restart the DNS Client service
Open Services
Win+R → services.msc.
Useful Commands
ipconfig /flushdnsnnslookup example.comBefore troubleshooting DNS, check whether it affects one device or the whole network — if every device fails the same nslookup test, the problem is upstream (router or ISP), not this PC.
Frequently Asked Questions
Is switching to Google or Cloudflare DNS always a good idea?
It’s a reasonable troubleshooting step and often faster than ISP defaults, but for a business network, coordinate with whoever manages internal DNS records first — some internal resources rely on the ISP or on-premise DNS server.
Why does the problem come back after a reboot fixes it temporarily?
That pattern usually means the DNS cache is being poisoned again by the same faulty upstream server — switching the DNS server address (Method 2) is the more permanent fix.
Conclusion
A flushed cache and a reliable public DNS server resolve the vast majority of Windows DNS errors — reserve router or ISP-level troubleshooting for cases where every device on the network is affected.
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