Testing your VPN’s encryption during live traffic reveals its vulnerabilities, helping you identify potential weak spots, like data leakages, and better understand connection drops or failures. This guide shows how to test your VPN’s encryption, ensuring you gain a comprehensive understanding during a free VPN trial, before committing to a purchase.
Content
- 1. Check IP Leakages via Command-Line Interface (CLI)
- 2. Use Wireshark to Detect Unencrypted Data Traffic
- 3. Explore BrowserLeaks’ Comprehensive VPN Testing Tools
- 4. Run Extended Tests with DNSLeakTest
- 5. Use Your VPN Provider’s Built-In Encryption Test Tools
1. Check IP Leakages via Command-Line Interface (CLI)
The surest indicator of a VPN with strong privacy controls is its ability to effectively mask your IP address, keeping your true location hidden. Easily check your IP address on a desktop via command-line interface (CLI) tools, and compare it with the results from a site like WhatIsMyIPAddress.
- Mac: type
ipconfig getifaddr en0for wired;en1for wireless in Terminal - Windows: open Command Prompt, and type
ipconfig /all. Look under all the IPv4 address fields.
If your actual location is revealed on the command line, it indicates that your VPN’s encryption is weak. We tested Windscribe’s free VPN servers. Generally, we do not recommend using a free VPN, and the results speak for themselves. There is a mismatch between the IPv4 address in the Ethernet adapter column and the one provided by the VPN.
2. Use Wireshark to Detect Unencrypted Data Traffic
Wireshark is a highly powerful, cross-platform application that will detect data leaks. It provides a detailed view of every data stream leaving your internal network. The installer is available for free on Windows, Mac, and Linux, and there’s even a portable version for Windows.
After installing Wireshark in Windows, launch Wireshark, and navigate to Capture -> Start. If you encounter an error, make sure the free edition of Npcap was installed.
Initially, you’ll see a continuous stream of IP address packets filling the screen. In this VPN example, I used one of the best free Wireguard-based servers. For the most part, there was no leakage, as the masked IP address was consistently visible. However, certain pink regions indicated a potential leak, which appeared to be an abnormal ARP packet revealing my true, unencrypted IP address.
While the above is a good VPN provider, its encryption is not foolproof. Even a tiny vulnerability to ARP poisoning (a man-in-the-middle attack) is concerning.
Also read: the terms VPN and proxy are used interchangeably, but they are different, as are VPN and firewall.
3. Explore BrowserLeaks’ Comprehensive VPN Testing Tools
If you’re not keen on inspecting data packets on your own, let BrowserLeaks handle it for you. The website offers various tools, including IP address checkers, WebRTC leak detection, WebGL reports, SSL/TLS client tests, canvas and font fingerprinting, and my personal favorite, the Geolocation API. Remember to turn the VPN on before you proceed with any of the tests.
The last test, “Geolocation API,” retrieves your device’s GPS location within a few meters, making it the definitive check to see whether your VPN is doing a good job. One of the leading VPN providers failed this test in our evaluation. However, it didn’t cause any WebRTC leaks, which is a hallmark of some of the best VPNs.
What I like most about BrowserLeaks is how comprehensive the tools are, while still being incredibly user friendly. You only need a browser and an active VPN.
Using a canvas fingerprint test makes it one of the few free online services that provides a clear overview of “browser fingerprinting” – your unique digital identity mapped by websites, based on your browsing habits and other unique factors.
Regrettably, the above VPN provider failed to safeguard my unique signature. It reported: “6 of 227,965 user agents share the same signature.” It is precisely the number of devices I am currently using, which is a bit spooky.
Check it out: is location spoofing the same as using a VPN? Know the differences between the two.
4. Run Extended Tests with DNSLeakTest
The Domain Name System (DNS) is central to everything we do online. When you use your real IP address, your device sends a DNS request to every website, exposing your actual IP address. A reliable VPN should completely mask your DNS to protect your device. However, many lower-tier or free VPNs often fail to safeguard this sensitive information.
DNSLeakTest is a website that identifies security vulnerabilities by running continuous tests. On its platform, you can choose between a standard test and a more comprehensive extended test. For a proper understanding of your VPN provider’s server security, it’s recommended to run these tests multiple times (on different servers). Besides checking for DNS leaks, you can also detect IP leaks and WebRTC leaks.
Related: DNSLeakTest can provide only one-time information on your VPN’s encryption. If you want historic data, GlassWire, a freemium provider, offers elaborate insights that are useful for network administrators.
5. Use Your VPN Provider’s Built-In Encryption Test Tools
On many leading VPN providers’ websites and apps, you’ll find the tools that offer a live overview of DNS tests, IP leaks, WebRTC leaks, and more. It is easy to argue that because these tests are provided by the VPN provider, they serve as a form of brand endorsement. Naturally, VPN services would appear flawless while highlighting flaws in other services.
While it’s true that VPN providers may favor their own services over others, the primary purpose of these tools is to monitor the performance of your VPN subscription. They help you check for live leakages, monitor ISP surveillance, and identify any attempts to throttle your connection speeds.
WebRTC leak test on
Surfshark
Top-tier VPNs often use obfuscated traffic to make your encrypted data resemble regular ISP packets, keeping it largely unnoticeable. But lesser VPN providers lack these features and can’t cover your tracks. If your VPN servers are not properly encrypted, there will be data leaks, which ISPs can use to introduce their fair usage policies and bandwidth restrictions.
Similar to tools like Wireshark, the built-in VPN encryption test tools allow you to closely monitor abnormal data packets or content filters introduced by your ISP. For example, ExpressVPN offers a Diagnostic information feature to keep a tab on ISP interferences in your network.
If you discover that your ISP is slowing down your VPN, the solution is simple: switch to a different VPN server. Most VPN providers continuously update and migrate their high-end smart servers, ensuring you stay ahead of any attempts to slow down your connection.
Testing VPN encryption is the most reliable way to assess a VPN’s capabilities. Some of the most secure VPNs meet the criteria that gives them a clean bill of health. Additionally, it’s crucial to understand the type of data a VPN aims to hide, including your location and other personal details.
Image credit: Pixabay. All screenshots by Sayak Boral.
Sayak Boral –
Staff Writer
Sayak Boral is a technology writer with over eleven years of experience working in different industries including semiconductors, IoT, enterprise IT, telecommunications OSS/BSS, and network security. He has been writing for MakeTechEasier on a wide range of technical topics including Windows, Android, Internet, Hardware Guides, Browsers, Software Tools, and Product Reviews.
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