(Credit: Zain bin Awais/PCMag/Getty Images)
Picture your personal information as a stream of data flowing from your computer and out into the open web. A VPN hides your computer as the source of that information by encrypting it. Encrypting your data scrambles its contents, making it appear to come from a completely different source. However, this obfuscation isn’t infallible. Even the best VPNs can experience server errors that may expose your actual information—this is called a leak. I go over how to tell when a leak is happening and what you can do to safeguard your data in the event of one.
This article was made possible in part by Proton VPN. It was written and edited independently without partner oversight.
How VPN Leaks Occur—and Why They Matter
For context, let’s review what happens when you visit a site over a regular internet connection. When you type in a domain name and hit enter, your browser pings that site, asking to be let in—also known as a DNS (Domain Name System) request. The site acts as a bouncer, checking the identity of anyone who is trying to get in and either approving or denying entry. Your browser sends your identifying information (your IP address), and the site records these details.
Using a VPN is like walking up to that bouncer with a rock-solid fake ID. You give the site a different IP address, which keeps your actual location and identity confidential. A leak happens when your connection to a VPN server falters. This lapse in protection exposes your actual information to the site and any other prying eyes, such as advertisers.
A leak may sound like a minor issue, but even a brief lapse in protection could result in unwanted attention. For example, a leak while torrenting can expose your activity to your internet service provider (ISP), which, depending on your location, could result in a warning letter or a fine. Similarly, those living in or traveling to countries with surveillance laws could face fines or other penalties if their actual traffic is exposed. But you don’t have to simply accept the risk and hope your identity doesn’t get leaked. There are some simple steps you can take to detect and stop a VPN leak.
How to Detect and Prevent a VPN Leak
The easiest way to check whether your VPN is secure is to use a browser-based leak detector, such as DNSLeak or IPleak. The image below shows what a protected connection should look like.
Recommended by Our Editors
(Credit: PCMag/IPleak)The IP address shown does not match my actual location, and you can see that no alternative DNS addresses have been found. The next image shows what a leaked connection may look like.
(Credit: PCMag/IPleak)I have blurred my IP address for privacy, but you can see that losing connection to the VPN server made my personal information visible. This leak happened because I switched off my VPN without closing my browser or enabling any safety features.
Luckily, it’s easy to prevent leaks entirely. Even the best service can experience server errors or outages, which is why most top options include a kill switch. I have a separate article on how a kill switch works, but the general idea is that, when triggered, it terminates your connection if your VPN falters for any reason. It stops all data from leaving your computer until the connection to a VPN server is reestablished.
(Credit: PCMag/Proton VPN)Kill-switch toggles are generally found in your VPN app’s dashboard; go there and ensure yours is switched on. If there’s an automatic setting, I recommend enabling it so the kill switch turns on whenever you’re connected to a VPN server.
Beyond a kill switch, you should disable any split tunneling rules so that you don’t accidentally allow unencrypted traffic to go out.
Additional Ways to Protect Your Privacy Online
Locking down your VPN and preventing leaks is a great first step toward securing your online privacy, but a VPN can’t protect you from every attack vector. I recommend pairing one with a set of other security tools to better secure your data. An antivirus can keep you safe from malware and trackers. A quality password manager can keep you safe in the event of a data breach, and multi-factor authentication can prevent your accounts from being compromised.