By carl 
You turned on your VPN, saw the green checkmark, and assumed you were covered. Your traffic is encrypted. Your IP is hidden. You can browse freely. That is the story most VPN apps sell you the moment you tap “connect.” But here is the uncomfortable truth: a VPN can appear to be working perfectly and still be leaking your real IP address, your DNS queries, or both. Your ISP sees everything. Your location is exposed. And your VPN’s dashboard never told you a thing.
Your VPN is only as private as its weakest leak.
- IP leaks, DNS leaks, and WebRTC exposure are three separate failure points , any one of them can undo your VPN’s protection silently.
- Running a leak test takes less than two minutes and shows you exactly what an outside observer can see about your connection right now.
- Each failure mode has a specific fix, and knowing which leak you have tells you exactly where to start.
The Scenario That Catches Most People Off Guard
Imagine you are traveling and connecting through hotel Wi-Fi. You fire up your VPN before opening your banking app. The connection says it is active. You do your business and close the laptop. What you did not know is that your VPN client had a small configuration gap. Every DNS request you made, every domain name your browser looked up, went straight through the hotel’s network unencrypted. Your VPN tunneled the content, but the map of everywhere you went was still visible in plain text.
This is not a fringe edge case. It happens regularly with popular VPN clients, especially on Windows, where the operating system sometimes routes DNS queries outside the VPN tunnel without warning. It also happens when your VPN drops unexpectedly and your traffic falls back to your regular connection before you notice.
The good news is that you can test for all of this in minutes. You do not need special software or technical expertise. You just need to know what to check and where to look.
What IP Leaks, DNS Leaks, and WebRTC Exposure Actually Mean
IP Leaks: Your Real Address Slipping Through
An IP leak happens when your actual IP address is visible to websites or services even though you are connected to a VPN. The most basic version of this is a simple tunnel failure. Your VPN client establishes a connection, something interrupts it, and for a few seconds or longer your traffic routes through your ISP’s network without protection.
The more subtle version involves IPv6. Most VPN clients tunnel IPv4 traffic correctly but forget about IPv6. If your ISP assigns you an IPv6 address and your VPN does not handle it, any site that supports IPv6 can see your real address alongside the masked IPv4 one. The two addresses appear side by side in the request headers. The site sees both.
DNS Leaks: The Map Your Traffic Leaves Behind
DNS stands for Domain Name System. Every time you type a website address, your device asks a DNS server to convert that name into an IP address. Think of it as the internet’s address book lookup service.
When you connect to a VPN, those lookups should go through the VPN’s own DNS servers, hidden inside the encrypted tunnel. A DNS leak means they are not. They are going to your ISP’s DNS servers instead, bypassing the tunnel entirely. Your ISP cannot read the content of your traffic, but they can see every domain you requested. Every site, every time.
The standard for encrypting DNS queries is outlined in the specification for DNS over HTTPS, but most consumer VPN clients do not implement it by default. That gap is part of why DNS leaks remain so widespread even among paid VPN services.
WebRTC Exposure: The Browser Bypass You Did Not Ask For
WebRTC is a browser technology built for real-time communication like video calls and peer-to-peer file transfers. The WebRTC standard requires browsers to discover the best network path between peers, which means they actively try to identify your real IP address, including local network addresses. This process can sidestep your VPN tunnel entirely and hand your true IP to any website that uses WebRTC, even when you believe you are fully masked.
Chrome, Firefox, and Edge are all affected. Many VPN browser extensions block WebRTC leaks, but standalone VPN apps often do not touch browser-level settings at all. If you use a desktop VPN app without a matching browser extension, this gap is almost certainly open.
How to Run a Leak Test and Read the Results
Before you trust your VPN with anything sensitive, run a VPN leak test to see what your current connection is actually giving away. This takes about two minutes and requires no setup. Here is how to approach it properly:
- Connect to your VPN as you normally would, using whatever server location you typically use.
- Open the leak test tool in the same browser you use for everyday browsing.
- Check the IP address shown. If you see your real home or ISP-assigned IP, your VPN has an IP leak.
- Look at the DNS servers listed. If they belong to your ISP rather than your VPN provider, you have a DNS leak.
- Check the WebRTC section. If a local or public IP appears that matches your real address, your browser is leaking through WebRTC.
- Run the test a second time after switching to a different VPN server to see if the results change. Inconsistent results point to intermittent leaks, which are harder to catch because they only appear when the tunnel hiccups.
Keep one browser tab with the test open and one without the VPN active for comparison. Seeing both side by side makes it immediately obvious when something is slipping through.
Fixing DNS Leaks: the Most Common Failure Mode
DNS leaks are the failure type you are most likely to encounter, and they are the most fixable. The root cause is almost always that your operating system is routing DNS queries outside the VPN tunnel. These are the most effective solutions:
- Enable DNS leak protection in your VPN client. Most reputable clients include this feature, but it is often buried in advanced settings and disabled by default. Look for it before anything else.
- Switch to a VPN that uses its own DNS servers. Some free or budget VPN clients rely on public DNS servers that are not routed through the tunnel at all, which makes leaks almost guaranteed.
- Set your DNS servers manually to ones your VPN provider controls, rather than letting your operating system decide. On Windows, this means changing adapter settings. On macOS, it is under Network Preferences for the active connection.
- Use a VPN protocol with built-in DNS handling. WireGuard handles DNS assignment as part of its configuration rather than leaving it to the OS, which removes one of the most common paths for a leak to occur.
Fixing IP Leaks and WebRTC Exposure
If your real IP is showing up in the test results, the first thing to check is your VPN client’s kill switch setting. A kill switch blocks all internet traffic the moment the VPN tunnel drops. Without it, your device reverts to your regular connection seamlessly and invisibly, and nothing on screen tells you it happened.
For IPv6 leaks specifically, many VPN clients have an IPv6 leak protection toggle in their settings. Turn it on. If your client does not offer that option, you can disable IPv6 on your network adapter entirely through your operating system’s network settings. It is a blunt fix, but it stops that particular leak reliably.
WebRTC exposure requires a browser-side fix because your VPN app cannot reach inside the browser to control that behavior. Here are the approaches that work:
- Install a browser extension specifically designed to block WebRTC IP leaks. Extensions like uBlock Origin include WebRTC protection in their settings panel.
- Disable WebRTC manually in Firefox by typing
about:configin the address bar, searching formedia.peerconnection.enabled, and setting it tofalse. This disables WebRTC entirely in that browser. - Use your VPN provider’s browser extension alongside the desktop app. Most providers offer extensions that handle WebRTC blocking as part of their feature set, addressing the gap that app-only installations leave open.
Why the Green Checkmark Is Not a Privacy Guarantee
Every VPN app shows you a connection status. None of them show you what is leaking. The interface confirms that the tunnel is active, but it cannot see what your browser is sending through WebRTC, or whether your OS is routing DNS outside the encrypted path. A green checkmark means the VPN client established a connection. It does not mean your traffic is fully contained.
This matters most in high-stakes situations. Using public Wi-Fi at airports or hotels. Accessing services that are restricted in your region. Working with sensitive documents on an untrusted network. In all of these cases, a partial VPN connection offers little more than false confidence, because it still exposes the most identifiable parts of your traffic while making you feel protected.
Running a leak test once when you first set up your VPN is a start. Running it each time you connect to a new network environment is better. A VPN that passed the test on your home network might behave differently on a corporate firewall or a mobile hotspot. Network conditions change. VPN behavior changes with them.
What Passing the Test Actually Means for Your Privacy
A VPN you have not tested is a VPN you cannot fully trust. The difference between a secure connection and a leaking one is often invisible until you check. IP exposure, DNS queries routing to your ISP, and browser-level WebRTC gaps are each fixable problems, but only once you know which one is happening on your specific setup.
The test itself takes two minutes. The fixes are direct once you know what you are dealing with. What you end up with is a connection you can actually rely on, not just one that looks right on the surface. That is the point of testing: replacing assumption with evidence.