How Do I Check My DNS for Leaks with mydns and Fix Them?

Updated

Connect to your VPN, open ipleak.net, and look at the DNS detection section. If any DNS server listed there belongs to your ISP or your local network instead of your VPN provider, your system is leaking DNS queries. The fix is to force DNS through the VPN tunnel — usually in the VPN client's settings, sometimes in your OS network settings — then re-run the check to confirm only VPN DNS appears.

This applies to any setup where you expect DNS to travel inside a VPN or proxy tunnel: VPN users, Tor users, and anyone testing a privacy tool. It does not apply if you are not using a tunnel — then seeing your ISP's DNS is normal.

What the mydns check actually shows

The DNS detection area on ipleak.net resolves a set of random hostnames through your system's configured resolvers and displays which DNS servers answered. The page states the logic plainly: "If you are now connected to a VPN and between the detected DNS you see your ISP DNS, then your system is leaking DNS requests."

Two things to note before you trust a result:

  • JavaScript must be enabled. The page shows "JavaScript required" placeholders for the DNS, WebRTC, and torrent sections until scripts run. A blank or "Pending, please wait" result means the check has not completed, not that you are clean.
  • The check reflects your resolver, not your traffic. It tells you which DNS servers your system used for these lookups. It does not prove every query goes the same way, but a leak here is a strong signal.

Step-by-step: run the check

  1. Disconnect the VPN first, then reconnect it. A stale tunnel can leave old resolver settings in place. Reconnecting forces the client to reapply its DNS configuration.
  2. Open ipleak.net in a browser and allow JavaScript.
  3. Wait for the DNS detection section to move from "Pending, please wait" to a list of DNS servers.
  4. Read the list. Compare each entry against:
    • Your VPN provider's published DNS server addresses.
    • Your ISP's DNS servers (often visible in your router's admin page or your OS network settings).
    • Your local router address (commonly 192.168.1.1 or similar) — a local resolver forwarding to the ISP is still a leak.
  5. Check the IP address details block on the same page. If the IP, ISP, and country shown match your VPN, the tunnel itself is working; a DNS leak alongside a correct IP means only the resolver path is broken.

If you see only your VPN's DNS servers, you are done. If you see ISP or local DNS, continue below.

Deciding whether it matters for you

Situation Is a DNS leak a problem?
Using a VPN to hide activity from your ISP Yes — the ISP can still see which domains you resolve
Using a VPN only to change your apparent location Usually minor, but it can break geo-unblocking if the ISP resolver returns local results
Not using any tunnel No — your ISP resolver is the expected path
Using Tor Browser Yes — Tor routes DNS through the circuit; a leak means the browser or system bypassed it

The page's own framing is worth keeping in mind: this is the kind of information every site you visit, plus its advertisers and embedded widgets, can collect. DNS is one channel among several.

Common causes of a DNS leak

  • VPN client DNS setting not applied. Some clients have a separate "use provider DNS" or "DNS leak protection" toggle that is off by default.
  • Manual DNS set in the OS. If you once set 8.8.8.8 or a similar public resolver in your network adapter, it can override what the VPN pushes.
  • IPv6 bypassing the tunnel. Many VPNs tunnel IPv4 only. If your ISP hands out IPv6 and your system prefers it, DNS can go out over IPv6 outside the tunnel. The related question on IPv6 leaks covers this path in detail.
  • WebRTC exposing requests. WebRTC uses STUN to discover your public IP and can reveal addresses the tunnel should hide. The page notes that if you are connected to a VPN and still see your ISP IP, your system is leaking WebRTC requests.
  • Split tunneling. If the VPN client is configured to route only some apps through the tunnel, the excluded apps use the system resolver.

Fixes by platform

VPN client settings (try first)

Look for options named "DNS leak protection," "Use VPN DNS," "Block outside DNS," or similar. Enable them, reconnect, and re-test. This is the least invasive fix and covers most cases.

Windows

  1. Open Settings → Network & Internet → your adapter → Edit DNS server assignment.
  2. Set it to Automatic (DHCP) so the VPN can push its resolver, or enter your VPN provider's DNS addresses manually.
  3. If IPv6 is the leak path, disable IPv6 on the adapter or set the VPN to handle it.

macOS

  1. Open System Settings → Network → your active service → Details → DNS.
  2. Remove any manually added DNS servers so the VPN's settings take effect.
  3. Check Advanced → TCP/IP for IPv6 configuration if leaks persist.

Firefox (WebRTC)

The page gives the exact steps: type about:config in the address bar, search for media.peerconnection.enabled, and double-click to set it to false. This disables WebRTC entirely, which stops the STUN-based IP discovery but also breaks WebRTC-dependent apps like browser video calls.

Chrome

The page's excerpt on Chrome is cut off, so treat the Firefox method as the documented example and check Chrome's current WebRTC handling separately if you need it.

Verify the fix

  1. Reconnect the VPN.
  2. Reload ipleak.net and let the DNS detection finish.
  3. Confirm the DNS list contains only your VPN provider's servers — no ISP entries, no local router address.
  4. Check the IP block still shows your VPN's IP and ISP.
  5. If you disabled WebRTC, confirm the WebRTC section no longer reports your ISP IP.

If the leak persists after all of the above, the tunnel itself may not be capturing DNS — try a different VPN protocol (for example, switch between OpenVPN and WireGuard if your client offers both) and re-test.

Quick reference

  • Check: ipleak.net → DNS detection section, JavaScript on, VPN connected.
  • Leak signal: ISP DNS or local DNS appears in the list.
  • First fix: enable DNS leak protection in the VPN client.
  • Second fix: clear manual DNS in OS network settings.
  • Third fix: disable IPv6 or WebRTC if either is the bypass path.
  • Confirm: re-run the check and see only VPN DNS.