Summary
Two of the most common security problems when using a VPN are:
DNS Leak
WebRTC Leak
These leaks can Your real IP, geolocation, and online activities even when a VPN is active. In this article, we take a closer look at how these leaks happen and the best ways to prevent them.
What is DNS Leak?
DNS stands for Domain Name System and is responsible for translating domain addresses like google.com into IP addresses. When you use a VPN, all DNS requests must go through the VPN tunnel.
But in case of DNS LeakInstead of sending requests to the VPN's DNS servers, the system sends them directly to your ISP's DNS.
The result?
Your real IP is exposed.
Actual location is recorded.
Your activities will be traceable.
DNS Leak is a serious privacy problem, but it is easily preventable.
What is WebRTC Leak?
WebRTC is a communication protocol used for video calling, screen sharing, and browser-to-browser communication.
But WebRTC can Extract your real IP directly from the system, even without an HTTP request and regardless of the VPN.
Why is it dangerous?
WebRTC works independently of VPN
Reads your real IP at the network system level
Sites can identify your IP with a simple JS script
Therefore, preventing WebRTC Leak is very essential.
Best Ways to Prevent DNS Leaks When Using a VPN
1. Use a VPN with Private DNS
The best and first step is to choose a VPN that has dedicated DNS.
The VPN should redirect all your requests to its internal DNS.
Features of a good VPN:
Private DNS
DNS over HTTPS or DNS over TLS
IPv6 support (or ability to disable IPv6)
If your VPN does not have private DNS, the chances of leaks are very high.
2. Disabling IPv6
Many VPNs do not support IPv6.
If IPv6 is enabled, requests are sent over your real network.
On Linux:
sudo sysctl -w net.ipv6.conf.all.disable_ipv6=1
On Windows:
Control Panel → Network → Adapter → Properties → IPv6 (uncheck)
3. Manually set DNS on the system
You can set the device's DNS to secure DNS.
For example, Cloudflare or Google DNS.
Example:
1.1.1.1
8.8.8.8
It is configurable on Windows, Mac, and mobile.
4. Enable Kill Switch on VPN
Kill Switch completely disconnects the internet if the VPN connection drops so that no DNS requests are sent from the real route.
5. Use DNS Leak Testing Tools
To ensure there are no leaks, perform the following tests:
DNS test
IPv6 test
WebRTC testing
If your ISP's real DNS is seen = you have a problem.
Best practices for preventing WebRTC leaks when using a VPN
1. Disable WebRTC in the browser
The best and most definitive method is to turn off WebRTC.
In Firefox
Go to the following address:
about:config
Search for the following option:
media.peerconnection.enabled
On false Set.
In Chrome
Chrome doesn't offer the ability to completely disable WebRTC by default, but you can use extensions:
WebRTC Control
WebRTC Leak Prevention
uBlock Origin (Enable WebRTC option)
2. Use secure browsers
Some browsers handle WebRTC:
Brave
Firefox
Tor Browser
Brave browser restricts WebRTC from the start.
3. Use a VPN with WebRTC Leak Protection
Some VPNs have built-in capabilities to prevent WebRTC leaks.
In this case, even if WebRTC is enabled, only the VPN IP will be displayed.
4. Use Firewall to Block WebRTC
In more advanced systems, you can block WebRTC ports and requests with a firewall.
For example, on Windows:
Block STUN ports
UDP block 3478
Prevent peer-to-peer communication
How do we make sure there are no leaks?
After applying the settings, you should test:
WebRTC test:
Run the test script in the browser and see if the real IP is visible.
DNS test:
Only the VPN server's DNS should be displayed.
IPv6 test:
If IPv6 is not enabled, no IP version 6 should be seen.
If your actual data is displayed in each test, it means it has not been fixed yet and you need to correct the settings.
Conclusion
To maintain online privacy, having a VPN alone is not enough.
DNS leaks and WebRTC are two major risks Which can reveal your real IP and activities. You can create complete security with the following methods:
Use a reputable VPN with private DNS
Disabling IPv6
Setting up secure DNS
Using the Kill Switch
Disabling WebRTC in the browser
Using WebRTC Leak Prevention Plugins
Implementing these settings ensures that when using a VPN, Your real information will never be revealed..
