Answer and scope

A VPN “hides” your IP address by routing your internet traffic through a VPN tunnel so that websites see the VPN server’s public IP instead of your device’s. Making sure you don’t leak your IP comes down to (1) confirming the VPN is actually active, (2) checking common leak paths like DNS and IPv6, and (3) minimizing gaps during connect/disconnect events.

Because every setup differs (OS, browser, network type, VPN client, routing rules), you can’t guarantee perfect results from theory alone. Treat “leak prevention” as something you validate with practical tests on your device.

Core explanation: how IP exposure can still happen

Even when a VPN is working, your IP can appear “leaked” for several reasons:

  • No tunnel yet (startup timing): Some devices or apps may make network requests before the VPN fully connects.
  • Traffic bypass (routing or interface selection): If certain traffic isn’t routed through the tunnel, it may reach the internet directly.
  • DNS resolution outside the tunnel: Your browser may contact a DNS resolver that reveals network metadata, or your system may fall back to non-VPN DNS.
  • IPv6 behavior: Many networks use IPv6, and some VPN setups don’t fully route IPv6 the way you expect, which can result in IPv6 reaching the internet directly.
  • Temporary disconnects: If the VPN drops briefly and there’s no effective “kill switch” behavior, the device may resume traffic using your normal network path.

To reduce these possibilities, you want your client and operating system to ensure that traffic only uses the VPN tunnel and that name resolution and IPv6 handling are consistent with that goal.

Differences and limits you should account for

Not every “IP leak” is the same thing, and your tests may show different outcomes depending on what you check.

  • Public IP vs. identity signals: Websites often learn more than just your IP (for example, account state, cookies, or device fingerprints). A VPN can help with IP-based visibility without making you indistinguishable.
  • LAN vs. WAN: A VPN mainly affects internet traffic routed to external servers. Local network (LAN) communication may still use your local addressing.
  • IPv4 vs. IPv6: A check that only looks for one protocol can miss leaks on the other. On IPv6-enabled networks, this matters.
  • Browser-specific behavior: Some browser settings, extensions, or browser DNS behavior can differ from the OS network settings. Your results may change when you test in different browsers.

A key limitation: even with good configuration, you can only be confident about leakage as observed on your device at the time of testing. Changes in Wi‑Fi networks, OS updates, or app updates can alter behavior.

Practical checks: a focused checklist

Use a small, repeatable set of tests so you can compare outcomes before and after connecting.

  1. Baseline: note your public IP without the VPN

    • Disconnect the VPN and record the public IP shown by a reputable “what is my IP” page.

  2. Confirm it changes with the VPN connected

    • Connect the VPN, wait until the client indicates it is fully connected, then check your public IP again.
    • If the IP doesn’t change, traffic may not be going through the VPN tunnel.

  3. Validate during reconnects and short drops

    • Toggle the VPN off and back on, then check whether your public IP and browsing behavior briefly revert to the original IP.
    • This helps reveal exposure windows when the VPN is not fully established.

  4. Check DNS and IPv6-related behavior

    • Look for tests that specifically evaluate DNS leak risks and IPv6 exposure.
    • If your network supports IPv6, ensure your system isn’t still using IPv6 outside the tunnel; some checks may show whether IPv6 is effectively handled.

  5. Review kill-switch / connectivity protection settings

    • If your VPN client offers a kill switch or “prevent traffic outside VPN,” enable it.
    • Then repeat your reconnect and disconnect tests to see whether non‑VPN traffic is blocked while the tunnel is down.

  6. Test with minimal variables

    • Use a clean browser session (or a different browser) and disable relevant extensions temporarily to reduce confounding factors.
    • Compare results on the same network first; then repeat on mobile data or another Wi‑Fi to see if the problem is network-specific.

Red flags and when to stop troubleshooting

Watch for these “evidence-style” warning signs:

  • Your public IP sometimes matches your baseline even though the VPN app shows “connected.”
  • DNS/IPv6 tests indicate requests are leaving through a non‑VPN path.
  • The issue occurs only on certain networks (common with IPv6 routing differences).

At that point, focus on identifying the variable that changes the outcome (network type, IPv6 availability, browser vs. OS settings, extensions, or VPN client connectivity protection). If you can’t get consistent, repeatable results, it may be more effective to treat the risk as “not fully validated” rather than assuming the configuration is correct.