What Is an IP Leak? How to Test and Stop It
An IP leak happens when your real internet protocol (IP) address becomes visible when you expect it to be hidden – most often while using a VPN, proxy, or privacy-focused browser setup. Your IP address can reveal your internet provider and approximate location. It normally cannot identify you by name or pinpoint your exact home address on its own, but exposing it may still weaken your privacy, especially if you are trying to avoid tracking or location-based restrictions.
What Is an IP Leak?
When you visit a website, your device needs to share an IP address so the site knows where to send data. A VPN is designed to replace your public IP with the VPN server’s IP address.
An IP leak occurs when part of your connection bypasses that protected route. The website, app, DNS provider, or another party may then see your real IP instead of the VPN IP.
The most common types include:
- Public IP leaks: Your real IPv4 or IPv6 address is exposed.
- DNS leaks: Your DNS requests go to your normal internet provider rather than through the VPN or chosen encrypted DNS service.
- WebRTC leaks: Browser real-time communication features reveal network information through connection candidates.
- IPv6 leaks: A VPN protects IPv4 traffic but fails to route IPv6 traffic safely.
WebRTC can expose more address information than people expect, which is why privacy-conscious applications may limit connections to relay candidates. MDN and the WebRTC standard both document this privacy consideration.
Why Do IP Leaks Happen?
IP leaks are usually configuration or software issues—not necessarily proof that a VPN is malicious. Common causes include:
- The VPN connection drops. Without a kill switch, traffic may immediately resume through your regular internet connection.
- DNS uses the wrong resolver. Your device may keep sending domain lookups to your ISP.
- Browser WebRTC behavior. Video, voice, and peer-to-peer features can expose connection metadata.
- IPv6 is not covered. Older or poorly configured VPN services may only protect IPv4 traffic.
- Extensions, apps, or split tunneling. Selected traffic may intentionally – or accidentally – bypass the VPN.
How to Test for an IP Leak
Run a test before relying on a VPN for sensitive browsing.
First, check your public IP with the VPN disconnected. Note the country, provider, and IP address displayed. Then connect to a VPN server in another region and test again.
A healthy result should show the VPN server’s IP address and approximate location—not your normal connection.
Next, check these areas:
- DNS: The listed DNS resolvers should belong to your VPN or chosen DNS provider, not your usual ISP.
- WebRTC: A test should not reveal your actual public IP address.
- IPv6: If your network supports IPv6, confirm it is either protected by the VPN or safely disabled.
Do not confuse the VPN server’s IP with a leak. If a test shows the VPN server’s country and provider, that is generally the expected result.
How to Prevent It
- Use a VPN with a kill switch – Enable the kill switch in your VPN settings. This feature blocks internet traffic if the encrypted VPN tunnel disconnects, reducing the chance that your real IP is exposed during a temporary outage.
- Check DNS protection – Use the VPN’s DNS protection feature if it provides one. You can also enable encrypted DNS in your browser or operating system. DNS over HTTPS encrypts domain lookups between your browser and a compatible DNS resolver, helping protect them from local network observers and many ISPs. Encrypted DNS is useful, but it does not replace a VPN: websites still need an IP address to communicate with your device.
- Review WebRTC settings – If you rarely use browser-based calls, review your browser’s WebRTC privacy controls or use an extension from a trusted source. If you rely on video meetings, test calls afterward – aggressive WebRTC blocking can break audio, video, and screen-sharing features.
- Make sure IPv6 is protected – Choose a VPN that explicitly supports IPv6, or use its documented IPv6 leak-protection setting. Disabling IPv6 can be a short-term workaround, but full VPN support is the cleaner long-term solution.
- Keep software current – Update your operating system, browser, VPN app, and network extensions. Privacy and networking behavior can change with software releases, and outdated apps may retain known bugs or insecure defaults.
IP Leak vs. DNS Leak: What’s the Difference?
An IP leak reveals the address assigned to your internet connection. A DNS leak reveals the services or domains your device is trying to access.
Both affect privacy, but they expose different information:
| Leak type | What may be exposed |
|---|---|
| IP leak | Your ISP, approximate region, and real public IP |
| DNS leak | The domains your device looks up |
| WebRTC leak | Network details, potentially including public or local addresses |
| IPv6 leak | Your real IPv6 address when IPv4 is protected |
Can a Website Owner’s Server IP Leak?
Yes. This is a separate issue from a visitor IP leak.
Website owners using a reverse proxy or content delivery network should ensure that DNS records, old hosting records, development subdomains, and direct-origin services do not expose the origin server’s IP address. For example, a proxied Cloudflare DNS record returns Cloudflare’s address to visitors rather than the origin IP, but unproxied records can reveal it. Cloudflare’s documentation explains this risk.
Final Thoughts
An IP leak can undermine an otherwise strong privacy setup, but preventing one is usually straightforward. Use a reliable VPN with a kill switch, protect DNS requests, review WebRTC and IPv6 behavior, and test your connection regularly. Privacy tools work best as a system. A VPN, encrypted DNS, updated software, and sensible browser settings together offer much better protection than any single feature alone.