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DNS_PROBE_FINISHED_BAD_CONFIG: What It Means & How to Fix It

6 min read

Key takeaway

DNS_PROBE_FINISHED_BAD_CONFIG means Chrome couldn't look up the site with your device's DNS servers, then tried Google Public DNS (8.8.8.8) and that worked. So your internet connection is fine and your DNS servers are the problem: wrong, down or broken. Restart your router, set your DNS back to automatic or to a working public resolver, and flush the DNS cache.

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DNS_PROBE_FINISHED_BAD_CONFIG explained: Chrome's two DNS probes, your DNS failing while Google Public DNS answers
DNS_PROBE_FINISHED_BAD_CONFIG explained: Chrome's two DNS probes, your DNS failing while Google Public DNS answers
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  1. What Is DNS_PROBE_FINISHED_BAD_CONFIG?
  2. How Chrome Decides It's Your DNS
  3. Where a Bad DNS Setting Comes From
  4. Check the Site Itself From Outside
  5. How to Fix DNS_PROBE_FINISHED_BAD_CONFIG
  6. DNS_PROBE Errors Compared
  7. Frequently Asked Questions

What Is DNS_PROBE_FINISHED_BAD_CONFIG?

Before a browser can open a website it has to turn the name, such as example.com, into an IP address. That lookup is DNS, and your device sends it to the DNS servers in its network settings: usually your router's, your internet provider's, or ones you or an app typed in.

When that lookup fails, Chrome doesn't just give up. It runs a quick test, a DNS probe, to work out why, and the code after DNS_PROBE_FINISHED_ is its answer. BAD_CONFIG is the answer Chromium's source describes as: "The DNS configuration is wrong, or the servers are down or broken." (Chromium)

How Chrome Decides It's Your DNS

The probe asks for a name that always exists, google.com, twice: once with your device's DNS settings, and once directly through Google Public DNS at 8.8.8.8 and 8.8.4.4. (Chromium) Then it compares the two:

The last column is the code after DNS_PROBE_FINISHED_. From EvaluateResults in Chromium's DNS probe service (dns_probe_service_factory.cc).
Your DNS serversGoogle Public DNSChrome shows
Answer correctly(not needed)NXDOMAIN: the site's name doesn't exist
FailAnswer correctlyBAD_CONFIG
FailCan't be reachedNO_INTERNET
FailReached, but answer with errorsINCONCLUSIVE

In Chromium's own words: "If the current DNS config is not working but Google DNS is, assume the DNS config is bad (or perhaps the DNS servers are down or broken)." (Chromium)

Where a Bad DNS Setting Comes From

Your device gets its DNS servers from one of a few places. Each can go wrong on its own:

  • Your router. Many home networks hand out the router itself as the DNS server. If its DNS forwarding stalls, every device on the network fails while the internet link is fine.
  • Your internet provider's DNS, which the router passes on. If those servers are down or broken, Chrome's probe sees exactly this result.
  • DNS addresses typed in by hand on the device or the router, for a service that has since changed or no longer works.
  • A VPN, ad blocker or security app that sets its own DNS while it runs. If it disconnects badly or is removed, its DNS setting can stay behind.
  • Chrome's own Use secure DNS setting, if it names a custom provider (the BAD_SECURE_CONFIG case).

Check the Site Itself From Outside

To be sure the website isn't the one at fault, look its name up from our servers instead of yours. If the lookup below finds its addresses, the site's DNS is fine and the problem is the DNS your device uses.

Look the site up with our DNS

To choose a DNS service that works well from your network, the DNS Speed Test times the big public resolvers from your own browser.

Once your device resolves names again, the DNS Leak Test shows which DNS servers it really uses, so you can see whether a new setting took effect.

How to Fix DNS_PROBE_FINISHED_BAD_CONFIG

Go through these in order and reload the page after each one.

  1. Restart your routerOn many home networks the router is your DNS server. Restarting it restarts its DNS forwarding, which clears one that has stalled.
  2. Turn off your VPN, ad blocker or security appIf one of them handles DNS, disconnect or pause it and reload. If the site loads, the app's DNS setting is the cause.
  3. Set your DNS back to automatic, or to a public resolverChrome's probe has just shown that Google Public DNS answers from your network, so a public resolver will work. Our DNS server not responding guide has the steps for Windows, Mac, iPhone and Android; the addresses are in our Google DNS and Cloudflare DNS guides.
  4. Flush the DNS cacheOld failed answers can stick around after the fix. See how to flush DNS on every system and in Chrome.
  5. Check Chrome's Use secure DNS settingIf it names a custom provider and you see BAD_SECURE_CONFIG, switch it to another provider or turn it off, then reload.

DNS_PROBE Errors Compared

Chrome's DNS probe ends in one of these. They look alike but point at different culprits:

Each code as it follows DNS_PROBE_ in Chrome, defined by Chromium's DNS probe (net_error_info.h, dns_probe_service_factory.cc).
DNS_PROBE_…Meaning and usual fix
STARTEDThe probe is still running: wait a moment. See DNS_PROBE_STARTED
FINISHED_NXDOMAINYour DNS works; the name doesn't exist: check the spelling. See our NXDOMAIN guide
FINISHED_BAD_CONFIGYour DNS fails; Google's answers: fix your DNS settings (this guide)
FINISHED_BAD_SECURE_CONFIGYour secure DNS provider fails; Google's answers: change Chrome's Use secure DNS setting
FINISHED_NO_INTERNETYour DNS fails and Google's can't be reached: fix the internet connection itself
FINISHED_INCONCLUSIVEGoogle's DNS answers with errors too: sign in to the Wi-Fi, or try another network

Is the site's DNS working, or just yours?

DNS Robot's free DNS Lookup resolves any name from our servers, from the root down, so you can see in seconds whether the site's DNS is fine and the problem is the DNS on your device.

Sources

  1. net_error_info.h (DnsProbeStatus), Chromium
  2. dns_probe_runner.cc (the google.com probe), Chromium
  3. dns_probe_service_factory.cc (EvaluateResults, Google Public DNS 8.8.8.8 / 8.8.4.4), Chromium

Frequently Asked Questions

What does DNS_PROBE_FINISHED_BAD_CONFIG mean?

Chrome couldn't look up the website's name with your device's DNS servers. It then tested Google Public DNS, which answered, so it concluded your DNS configuration is wrong or your DNS servers are down or broken. Your internet connection itself works.

Is it my internet or my DNS?

Your DNS. Chrome only shows BAD_CONFIG after it has reached Google's public DNS servers (8.8.8.8 and 8.8.4.4) from your network, which proves the connection works. If Google's DNS couldn't be reached either, Chrome would show DNS_PROBE_FINISHED_NO_INTERNET.

How do I fix DNS_PROBE_FINISHED_BAD_CONFIG on Windows?

Restart your router, turn off any VPN or ad blocker that handles DNS, then set your network adapter's DNS back to automatic or to a public resolver such as Google's or Cloudflare's. Flush the DNS cache with ipconfig /flushdns and reload the page.

Will changing my DNS to 8.8.8.8 fix it?

Usually, yes. The error itself shows that Google Public DNS answers from your network, because Chrome's probe just used it. Setting your device or router to a working public resolver replaces the DNS servers that are failing.

What's the difference between BAD_CONFIG and NXDOMAIN?

With NXDOMAIN your DNS servers work, so Chrome concludes the site's name doesn't exist and you should check the spelling. With BAD_CONFIG your DNS servers fail while Google's work, so the fault is in your DNS settings, not the website.

What is DNS_PROBE_FINISHED_NO_INTERNET?

It's the same probe with a worse result: your DNS failed and Google's public DNS couldn't be reached either, so Chrome assumes the internet connection is down. Check the cable, Wi-Fi or router before changing any DNS settings.

What is DNS_PROBE_FINISHED_BAD_SECURE_CONFIG?

It's BAD_CONFIG for Chrome's Use secure DNS setting: the secure DNS provider you chose isn't working while Google's DNS answers. Switch the setting to another provider or turn it off, then reload.

Does restarting the router help?

Often. On many home networks the router acts as the DNS server for every device, so when its DNS forwarding stalls, every site fails with this error while the internet link is fine. A restart clears that, which is why it's the first fix to try.

About the author

Shaik Vahid

Founder of DNS Robot. Vahid spent years in web hosting support fixing domains, DNS records, SSL certificates and email delivery for customers. He builds DNS Robot's tools and writes these guides from the errors people actually hit.

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