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Cybersecurity 5 min readBy Mehadi ShawonPublished Updated

How to Check if Your DNS Is Leaking (Free 60-Second Test)

A DNS leak exposes the sites you visit even with a VPN on. Here's how to test for one in 60 seconds and fix it on any device.

Glowing DNS server icon with a golden water drop leaking out representing a DNS leak test
Quick answer

How to Check if Your DNS Is Leaking (Free 60-Second Test)

To test for a DNS leak: connect your VPN, visit dnsleaktest.com or browserleaks.com/dns, and run the extended test. If any IP or hostname belongs to your ISP (not your VPN), you have a DNS leak and your browsing is partially exposed.

A VPN that leaks your DNS queries is barely better than no VPN at all. Your IP looks hidden, but your ISP (and anyone watching) still sees every domain you visit. Here's a 60-second test and the exact fixes for each platform.

The 60-Second Test

  1. Connect to your VPN.
  2. Open dnsleaktest.com (or browserleaks.com/dns).
  3. Click 'Extended test'.
  4. Look at the IPs and hostnames returned. If any belong to your ISP, you have a leak.
Glowing DNS server icon with a golden water drop leaking out representing a DNS leak test

Common Causes of DNS Leaks

  • Windows Smart Multi-Homed Name Resolution sending queries to all interfaces.
  • IPv6 traffic bypassing an IPv4-only VPN tunnel.
  • Router-level DNS overriding the VPN's DNS.
  • Browser-level DNS-over-HTTPS using a different provider.
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Fix It on Windows

Disable IPv6 on your active adapter and turn off Smart Multi-Homed Name Resolution via Group Policy. Most modern VPN clients have a 'Leak Protection' toggle that does both automatically — turn it on.

Fix It on Mac and Linux

Set DNS manually to your VPN's resolver, or to a public privacy DNS like 1.1.1.1 (Cloudflare) or 9.9.9.9 (Quad9).

Fix It on a Router

Log into your router admin and clear any hardcoded DNS servers — let DHCP from the VPN take over. Re-test.

Check your current public IP and ISP — useful before/after the leak test.

Run IP Lookup

Frequently Asked Questions

What's the difference between a DNS leak and an IP leak?+

A DNS leak exposes the sites you visit; an IP leak exposes your real IP address. Both defeat the privacy promise of a VPN — test for both.

Can a free VPN cause DNS leaks?+

Yes — many free VPNs don't run their own DNS servers, so queries fall back to your ISP. This is one of the biggest hidden costs of free VPNs.

Does disabling IPv6 fix DNS leaks on Windows?+

Often yes. Windows queries IPv6 DNS in parallel by default, which can bypass VPN tunnels that only handle IPv4.

How often should I re-test for DNS leaks?+

After every OS update, VPN client update, or router reboot — these are the three most common causes of new leaks.

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