What an IP leak means (and what you can’t fully prevent)

An IP leak happens when your real network information becomes visible to a website or service instead of (or in addition to) the information coming from your VPN connection. In practice, you usually can’t make every possible leak scenario impossible, but you can reduce the most common causes by using correct VPN settings and by verifying behavior after changes.

A simple model: where leaks come from

A helpful way to think about leaks is: your device needs to route network traffic through the VPN, and every supporting system (like name resolution) needs to follow the same path.

Common failure points include:

  • The VPN connection drops while your device continues sending traffic.
  • DNS resolution happens outside the VPN path.
  • IPv6 traffic bypasses IPv4 protections.
  • Browser-level networking or “smart” features temporarily use alternate routes.

The key protections to enable

Start with VPN features and settings that directly address the failure points above:

  • Enable a kill switch (or network lock) so traffic is blocked when the VPN is not connected.
  • Ensure DNS handling is configured to use the VPN’s DNS path (often labeled DNS leak protection or similar).
  • Check IPv6 handling. If your VPN does not protect IPv6 the way you expect, that can reintroduce exposure even when IPv4 looks fine.
  • Prefer a full-device VPN mode (not only an app-specific mode) when your goal is to avoid gaps between apps and system networking.

Because VPN implementations differ, treat these as verification targets, not universal names. If your VPN client uses different labels, look for the same intent: “block traffic on disconnect” and “route DNS through the VPN.”

Differences that change your risk

Different leak types require different checks:

  • Public IP vs. DNS exposure: even if your public IP test looks correct, DNS queries may still reveal information depending on how name resolution is performed.
  • Browser vs. system behavior: some browsers use features that can change networking behavior. Testing in more than one browser (or a fresh profile) helps distinguish browser-specific effects from system-level routing.
  • IPv4 vs. IPv6: some test pages primarily report one protocol. Confirm which address family is being tested and whether IPv6 is present.

Practical checks you can run (without guessing)

You can verify the effectiveness of your current setup with controlled checks:

  1. With the VPN connected, test your visible public IP in at least two different browsers (or profiles). Compare the results.
  2. Disconnect the VPN and confirm that normal browsing does not work. If it still loads, a kill switch/network lock may be missing or not applied correctly.
  3. Enable and review DNS protection settings, then test DNS behavior using a reputable diagnostic page (for IP and DNS-related signals). If results differ before and after toggling DNS-related options, that indicates leakage or routing differences.
  4. If your system has IPv6 enabled, repeat the checks after you adjust IPv6 handling within the VPN client (or confirm what the client reports about IPv6 support).

If any test contradicts your expectation, change one setting at a time and re-check. That approach makes it easier to identify which specific component (disconnect handling, DNS path, IPv6, or app routing mode) is responsible.

Limits and the main exception to watch

The biggest practical exception is when your VPN client is not protecting the same traffic you’re testing. For example, an app-only VPN mode may leave other traffic outside the VPN, and browser profiles/extensions can also affect what you observe. Your results are only as reliable as the scope of the VPN protection and the consistency of your tests.

If you need stronger assurance, focus on the two controllable pillars: (1) preventing traffic during disconnects, and (2) routing DNS and all relevant IP protocols through the VPN path.