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What to do if NymVPN is leaking DNS/WebRTC and IPv6 addresses?

Updated

All NymVPN apps include built-in protection against DNS, WebRTC, and IPv6 leaks. The protection is active by default. If you're seeing your real IP or real DNS resolver in a leak test while connected, it's almost always a fixable client-side configuration or an old app version. Keep NymVPN updated, then work through the checks below.

What these leaks are

  • DNS leak. Your device asks "where is example.com" of a DNS resolver outside the VPN tunnel, often your ISP's. Even if your traffic is encrypted, an observer at the resolver sees the sites you're looking up.
  • WebRTC leak. Browsers use WebRTC for video/audio calls. WebRTC can request your local IP directly, bypassing the VPN. This is a browser-level issue, not a VPN-level one.
  • IPv6 leak. If your device has IPv6 enabled but the VPN tunnel only carries IPv4, IPv6 traffic can escape outside the tunnel and expose your real IP.

How NymVPN prevents each

  • DNS: NymVPN routes all DNS queries through the VPN tunnel by default. For details on the privacy properties of Nym's DNS handling see How to use Domain Name System (DNS) privacy in NymVPN?
  • WebRTC: NymVPN's tunnel covers WebRTC by design. Some browsers have additional WebRTC features that can request local IP information; if you see a WebRTC leak, see "Browser-specific notes" below.
  • IPv6: NymVPN blocks or routes IPv6 traffic depending on platform to prevent IPv4-only tunnels from leaking IPv6.

How to test for a leak

  1. Connect to NymVPN and confirm the app shows "Connected".
  2. Visit dnsleaktest.com and run the Extended Test. Every DNS server listed should belong to a NymVPN gateway, not your ISP.
  3. Visit browserleaks.com/webrtc. Your "Public IP Address" should be the NymVPN gateway IP; "Local IP Address" may be a private range (like 192.168.x.x), which is fine and not a leak.
  4. Visit ipv6-test.com. If you see "No IPv6 address detected" while NymVPN is connected, that's expected for platforms where IPv6 is blocked. If you see your real IPv6 address, the tunnel is leaking IPv6.

If a leak is detected, try this

  1. Update NymVPN to the latest version. You may be running a very old version of the app.
  2. Restart your device. Especially if you've had multiple VPN clients installed historically, leftover routing rules can interfere.
  3. Disable other VPN, firewall, or proxy software. Conflicts with other clients are a frequent cause.

Browser-specific notes

  • Firefox: open about:config and set media.peerconnection.enabled to false to disable WebRTC entirely (useful if you don't need video/audio calls).
  • Chromium-based browsers (Chrome, Brave, Edge): choose a browser with WebRTC controls. Brave, for example, has built-in toggles under privacy settings.
  • Tor Browser: WebRTC is disabled by default; no further action needed.

If the leak persists

If you've worked through the above and a leak still shows in testing, contact Nym Support with:

  • The leak-test URL and a screenshot of the result
  • Your platform (Windows, macOS, Linux, Android, iOS) and version
  • Your NymVPN app version
  • Logs and diagnostics from affected connection attempts

All leak reports are taken seriously and prioritized.

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