VPN Leak Test: How to Prevent IP Leaks With Your VPN

One of the primary reasons people use a Virtual Private Network (VPN) is to hide or disguise their true IP address while they’re online. There are several reasons why people may want to hide their IP address, but the fact remains that this is the central job of a VPN.

By using a VPN, a user can get around the ban on their normal IP address. Better yet, websites have no way of finding out the true IP address.

That is, unless their VPN has a leak. When you have a VPN leak, you no longer have the protection your VPN is designed to provide.

A VPN leak occurs when the VPN does not successfully disguise the user’s IP address, DNS requests, or other personal information. This defeats the purpose of the VPN and exposes user data to malicious actors online.

Recently, there have been several newsworthy incidents in which VPN providers have experienced breaches due to leaks.

In 2023, a report revealed that 360 million user accounts were exposed in a leak from SuperVPN, a free VPN service
In 2024, it was estimated that 2.5 billion Android users were at risk of VPN leaks
A recent technique called Tunnel Vision pushes VPN users off of their protected networks without their knowledge; this has the potential to be used on all VPNs
A potential flaw in the WebRTC of your browser could also reveal your private info, even when using a VPN

All of this is concerning, and it is important to know how to check if your VPN has a leak–and how to run a VPN leak test from WhatIsMyIPAddress.com.

Reasons for using a VPN

There isn’t just one single reason to use a VPN. Many people choose VPNs for a combination of reasons, including:

Increased overall security on your connected devices
No more connecting to unsecured public wifi
Getting around location-based limits on access
Being able to bypass internet censorship in countries that limit internet access
Better privacy protection from ISPs
Successfully torrenting more data

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What makes a VPN susceptible to leaks?

In general, VPNs increase your security, but not if there is a leak. Understanding why leaks happen is an important step in avoiding them.

Let’s take a look at several of the potential causes of VPN leaks.

Free VPNs have increased risks of leaks

Free VPN platforms are great for budget-conscious users, but they come with limitations. Those limitations can cause security risks.

Specifically, free VPNs may have:

limited resources for security updates and infrastructure maintenance
outdated encryption protocols
overcrowded servers

Worst than that, some free VPNs may choose to collect and sell user data, which puts your information at risk.

Hackers can use the TCP TunnelVision technique

This relatively new attack method works by exploiting how VPNs handle TCP connections.

The TunnelVision attack is a clever trick that can compromise the security of most VPNs. This attack can fool your device into sending some or all of your data outside of the VPN’s secure connection without you realizing it.

Imagine your VPN as a secure underground tunnel, and the TunnelVision attack as a sneaky detour that redirects your data to the surface where it’s visible. This happens when you connect to a network controlled by an attacker, typically a public Wi-Fi hotspot. Your device thinks it’s still using the secure VPN tunnel, but in reality, your data is exposed.

This allows the attacker to potentially see, modify, or block your internet activity, all while your VPN appears to be working normally. The attack is particularly concerning because it affects most VPNs and operating systems, making it a significant threat to online privacy and security for VPN users.

Choosing a paid, well-maintained VPN provider may offer additional protection from this kind of attack because they should be faster about patching this vulnerability.

WebRTC Leaks

There is a special interface (program) in most Internet browsers (Chrome, Firefox, etc.) called Web Real Time Communication, or WebRTC, and that’s where the potential for vulnerability is.

However, WebRTC isn’t a flaw at all. It’s actually a special facet of your Web browser.

WebRTC allows computers on different networks to perform special browser-to-browser applications, such as voice calling, video chats, file sharing and more.

But as it turns out, in the hands of a technically savvy person, WebRTC can be tricked into revealing your actual IP address, even if you’re actively using a VPN! That’s certainly not what you would expect or want.

Here’s how websites are fighting back: They have an IT person “write a few lines of code” (in other words, create a mini-program) to initiate or imitate a WebRTC-type connection with your browser. In the process, the program tricks the VPN into revealing the actual IP address. The website can then use the information to block the active connection.

Think of it as having a fake driver’s license pasted over your real license. WebRTC is like an x-ray machine: Websites can see through the fake IP address and identify the real one…and then block it.

(Check out the end of this article for a useful tool for a VPN leak check!)

Additional vulnerabilities

Some other potential security issues with VPNs include:

DNS leaking (Need to do a DNS IP leak test? Use this DNS leak test tool)
IPv6 leaking
Kill switch failures
Outdated VPN protocols
Split tunneling misconfigurations

How to check for VPN leaks

If you have a VPN account, here’s how you can check your account for WebRTC leaks:

Open your browser, go to WhatIsMyIPAddress.com and jot down your IP address.
Log in to your VPN, choose a remote server (as you regularly do) and verify that you’re connected. Wait a few minutes.
Revisit WhatIsMyIPAddress.com and take note of your IP address once more. You should see a new IP address, provided by your VPN connection.
Here is the key step: Visit this WebRTC test page and note the IP address displayed on the page.
If the WebRTC test shows your normal IP address, then your browser is leaking your ISP-provided address to the world.

You can count on WhatIsMyIPAddress.com around the clock to help you verify your Internet connection and determine if your VPN is leaking your IP address.

How to fix DNS leaks

A DNS leak in a VPN is a different kind of security flaw than a WebRTC leak. Essentially, it means that your device is sending lookup requests (DNS queries) outside of the VPN’s protection.

Normally, when you use a VPN, your DNS queries go through the VPN’s encrypted tunnel. When you have a DNS link, these requests bypass the VPN and go directly to your regular internet provider (or other DNS servers). This compromises the privacy and anonymity that your VPN is supposed to give you.

To fix leaks like this, you have a few options:

Enable DNS leak protection using a built-in feature, if it is available
Choose a VPN with a kill switch that cuts off your internet as soon as the VPN drops
Disable IPv6 if your VPN doesn’t support it
Use DNS leak testing tools

How to fix a WebRTC leak.

There’s no need to panic. You might be able to fix the VPN leak on your own, either by disabling WebRTC on your browser or installing a browser plug-in that blocks it.The Chrome, Firefox, and Opera browsers operate with WebRTC active, or enabled, by default; Safari and Internet Explorer do not. (If the WebRTC test showed your true IP address, you have it enabled.)

Here’s how to disable it:

For Chrome and Opera: Choose a Chrome extension like WebRTC Leak Prevent, Wasy WebRTC Block, PureVPN Chrome Extension, or WebRTC Control.
For Firefox: There are two options: 1) Disable WebRTC directly by opening a tab and going to “about:config” in the address bar. Click “I accept the risk!” to continue. Once you have accepted the risk, type media.peerconnection.enabled into your search bar, then double-click the search result, changing the value column to “false.”

Keep in mind that disabling WebRTC may disrupt some Web apps and services, such as chat or other services involving your computer’s microphone or camera. If that happens, you can always enable WebRTC temporarily to fix that.