You've connected to a VPN. Your IP address is masked. Your traffic is encrypted. You feel safe and anonymous online.
But there's a critical vulnerability that many VPN users don't know about: DNS leaks.
Even with your VPN active, your real location and browsing history can be exposed through DNS queries sent outside the encrypted tunnel. This silent leak undermines your entire privacy setup—and you might not even know it's happening.
In this guide, we'll explain what DNS leaks are, how they happen, and most importantly, how to protect yourself.
Table of Contents
What is DNS and Why Does It Matter?
DNS (Domain Name System) is like the internet's phone book. When you type "google.com" into your browser, a DNS server translates that human-readable address into an IP address (like 172.217.164.78) that computers understand.
Every time you visit a website, your device sends a DNS query to figure out where that website lives. This happens automatically in the background—you never see it.
The Privacy Problem
Here's the issue: DNS queries are not encrypted by default. Your internet service provider (ISP) can see every DNS request you make, which means they know every website you visit, even if you're using HTTPS.
This is where VPNs come in. A good VPN routes your DNS queries through its own secure servers, keeping your browsing history hidden from your ISP and other snoopers.
Did You Know?
Your ISP can build a detailed profile of your online behavior just by logging your DNS queries—no need to decrypt your traffic. This data is often sold to advertisers or handed over to authorities.
What Are DNS Leaks?
A DNS leak occurs when your DNS queries bypass the VPN tunnel and go directly to your ISP's DNS servers instead of your VPN's secure DNS servers.
When this happens:
- Your VPN encrypts your internet traffic (good)
- But your DNS requests leak outside the tunnel (bad)
- Your ISP can still see which websites you're visiting
- Your real location and identity can be exposed
Think of it like this: You're sending a secret letter through a secure courier service (VPN), but the return address on the envelope is still visible (DNS leak). Anyone can see where the letter is going, even if they can't read what's inside.
How DNS Leaks Happen
DNS leaks can occur for several reasons:
1. Poor VPN Configuration
Some VPNs don't properly configure your system to route all DNS traffic through the VPN tunnel. This is especially common with free or low-quality VPN services.
2. Operating System Behavior
Windows, macOS, and other operating systems sometimes send DNS queries to multiple servers simultaneously to speed up browsing. If your ISP's DNS server responds faster than your VPN's server, your OS might use that response—causing a leak.
3. IPv6 Leaks
Many VPNs only protect IPv4 traffic. If your ISP supports IPv6 and your VPN doesn't block it properly, your DNS queries can leak through the IPv6 connection.
4. Transparent DNS Proxies
Some ISPs use transparent DNS proxies that intercept DNS queries even when you've configured different DNS servers. This can cause leaks that are difficult to detect.
5. VPN Connection Drops
If your VPN connection drops unexpectedly and doesn't have a kill switch, your device will revert to your ISP's DNS servers until the VPN reconnects.
Warning
DNS leaks are silent. You won't see any warnings or notifications. Your VPN might show as "connected" while your DNS queries are still leaking to your ISP.
Why DNS Leaks Are Dangerous
DNS leaks undermine the entire purpose of using a VPN. Here's what's at risk:
1. Your ISP Can Track You
Even with a VPN, your ISP can see every website you visit through leaked DNS queries. They can log this data, throttle specific sites, or sell your browsing history.
2. Your Real Location Is Exposed
DNS queries reveal your real IP address and location to DNS servers. If you're trying to bypass geo-restrictions or censorship, DNS leaks can give you away.
3. Advertisers Can Profile You
DNS queries help build detailed profiles of your interests and behavior. This data is valuable to advertisers and data brokers.
4. Government Surveillance
In countries with strict internet censorship, DNS leaks can reveal that you're trying to access blocked content—potentially putting you at risk.
5. False Sense of Security
The most dangerous aspect of DNS leaks is thinking you're protected when you're not. You might share sensitive information believing your VPN is keeping you anonymous, but DNS leaks are silently exposing you.
How to Detect DNS Leaks
The good news: testing for DNS leaks is simple and takes less than 30 seconds.
Step-by-Step DNS Leak Test
- Connect to your VPN and choose a server in a different country
- Visit a DNS leak test website like dnsleaktest.com or ipleak.net
- Run the standard or extended test
- Check the results:
- ✅ No leak: All DNS servers belong to your VPN provider or are in the VPN server's country
- ❌ DNS leak: You see your ISP's DNS servers or servers in your real country
Pro Tip
Run the extended test for more thorough results. It queries multiple DNS servers and can detect intermittent leaks that the standard test might miss.
What to Look For
When reviewing your test results, pay attention to:
- DNS server location: Should match your VPN server's location, not your real location
- ISP name: Should show your VPN provider, not your actual ISP
- IPv6 addresses: If any appear and you're connected to an IPv4 VPN server, that's an IPv6 leak
How to Prevent DNS Leaks
Protecting yourself from DNS leaks requires a combination of choosing the right VPN and proper configuration.
1. Use a VPN with Built-In DNS Leak Protection
The easiest solution is to use a VPN that automatically handles DNS queries securely. Free VPN includes built-in DNS leak protection that routes all your DNS traffic through our encrypted servers—no extra configuration needed.
2. Enable IPv6 Leak Protection
Make sure your VPN blocks or disables IPv6 traffic if it doesn't fully support it. Free VPN automatically handles this for you.
3. Use a Kill Switch
A kill switch blocks all internet traffic if your VPN connection drops, preventing DNS leaks during reconnection. Free VPN's kill switch activates automatically whenever the VPN disconnects.
4. Change Your DNS Settings Manually (Advanced)
If your VPN doesn't offer DNS leak protection, you can manually configure your system to use secure DNS servers like:
- Cloudflare: 1.1.1.1 / 1.0.0.1
- Google Public DNS: 8.8.8.8 / 8.8.4.4
- Quad9: 9.9.9.9 / 149.112.112.112
However, this still routes your DNS queries outside your VPN tunnel—it just sends them to a third party instead of your ISP.
5. Disable Teredo and Smart Multi-Homed Name Resolution
On Windows, these features can cause DNS leaks. To disable them:
- Open Command Prompt as Administrator
- Run:
netsh interface teredo set state disabled - Run:
netsh interface ipv6 6to4 set state disabled - Restart your computer
Important
Manual DNS configuration and system tweaks can be complex and may break other functionality. The safest approach is using a VPN with automatic DNS leak protection like Free VPN.
Free VPN's Built-In DNS Leak Protection
At Free VPN, we take DNS privacy seriously. Every connection includes comprehensive leak protection:
🔒 Our DNS Security Features
- Private DNS Servers: We operate our own DNS servers in every location—no third-party DNS providers
- Automatic DNS Routing: All DNS queries automatically go through the VPN tunnel
- IPv6 Leak Prevention: IPv6 traffic is either routed through the tunnel or blocked completely
- Kill Switch Protection: If the VPN drops, all traffic stops—including DNS queries
- No DNS Logs: We don't log any DNS queries, ever
- DNS-over-HTTPS Support: For additional encryption on supported platforms
How It Works
When you connect to Free VPN:
- Your device's DNS settings are automatically reconfigured
- All DNS queries are encrypted and sent through the VPN tunnel
- Our secure DNS servers handle the lookups
- Responses come back through the encrypted tunnel
- When you disconnect, your original DNS settings are restored
This happens automatically—no manual configuration required.
Verify Your Protection
After connecting to Free VPN, run a DNS leak test at dnsleaktest.com. You should see only our DNS servers, never your ISP's servers or your real location.
Key Takeaways
- DNS leaks expose your browsing history and real location even when using a VPN
- DNS queries are not encrypted by default, making them vulnerable to snooping
- Test for DNS leaks regularly using tools like dnsleaktest.com
- Choose a VPN with built-in DNS leak protection (like Free VPN) for automatic security
- Always enable your VPN's kill switch to prevent leaks during connection drops
- IPv6 leaks are common—make sure your VPN blocks or properly routes IPv6 traffic
Conclusion
DNS leaks are one of the most overlooked privacy vulnerabilities in VPN use. Even the most security-conscious users can be exposed if their VPN doesn't properly handle DNS queries.
The good news? Protecting yourself is simple when you use a VPN that prioritizes DNS security. Free VPN automatically prevents DNS leaks with zero configuration required—just connect and browse with confidence.
Don't let DNS leaks undermine your privacy. Test your current VPN today, and if you see leaks, switch to a provider that takes your security seriously.
