What Is an IP Leak?

An IP leak is a critical privacy failure that occurs when your real IP address becomes visible to websites, services, or third parties despite using a VPN. This exposure defeats the entire purpose of a VPN and can reveal your actual location, Internet Service Provider (ISP), and potentially your identity. Understanding what IP leaks are and how to prevent them is essential for anyone serious about online privacy.

IP Leak Definition: The Basics

What Is an IP Address?

Before understanding IP leaks, you need to know what an IP address is. An IP (Internet Protocol) address is a unique numerical identifier assigned to every device connected to the internet. Think of it like your home's street address — it tells other devices where to send data.

There are two types of IP addresses:

• IPv4: The traditional format (e.g., 192.168.1.1), consisting of four numbers separated by periods
• IPv6: The newer format (e.g., 2001:0db8:85a3:0000:0000:8a2e:0370:7334), designed to accommodate more devices

Your IP address reveals several pieces of information:

• Your general geographic location (city or region)
• Your Internet Service Provider (ISP)
• Your approximate time zone
• In some cases, your organization (if using a business network)

What Is an IP Leak?

An IP leak occurs when your real IP address is exposed despite using a VPN that should hide it.

Here's the analogy: Imagine you're sending a letter but don't want the recipient to know your real address. You ask a friend (the VPN) to receive your letters and forward them with their return address instead. An IP leak is like accidentally writing your real address on the envelope anyway — defeating the entire purpose of using your friend as an intermediary.

How IP Leaks Happen

IP leaks can occur for several technical reasons, even with reputable VPN services:

1. VPN Connection Drops (Reconnection Leaks)

VPN connections can temporarily drop due to network instability, server issues, or software bugs. During these brief moments, your internet traffic may revert to your normal (unprotected) connection, exposing your real IP address.

Analogy: Imagine you're in a tunnel (the VPN). If the tunnel suddenly collapses for a second, you're briefly exposed to the open sky (the internet) before the tunnel rebuilds itself.

2. IPv6 Leaks

Many VPN services only route IPv4 traffic through their encrypted tunnel but fail to handle IPv6 traffic properly. If a website requests your IPv6 address and your VPN doesn't block it, your real IPv6 address leaks.

Why this happens: IPv6 is the newer internet protocol, and some older VPN software wasn't designed to handle it. Your operating system might prefer IPv6 connections when available, bypassing the VPN entirely.

3. Split Tunneling Misconfigurations

Split tunneling is a VPN feature that lets you choose which apps or websites use the VPN and which use your regular connection. If misconfigured, some traffic may leak outside the VPN tunnel, exposing your IP address.

Example: You configure your VPN to only tunnel web browser traffic, but a background application (like a torrent client) continues using your real IP address.

4. VPN Kill Switch Failures

A kill switch is a safety feature that blocks all internet traffic if your VPN connection drops, preventing leaks. However, if the kill switch malfunctions or isn't enabled, your traffic continues flowing through your regular connection during VPN disconnections.

5. Operating System Network Settings

Some operating systems (particularly Windows and macOS) have network settings that can bypass VPN connections:

• Teredo tunneling (Windows): A protocol designed to help IPv6 traffic traverse IPv4 networks, but it can leak your real IP
• Smart Multi-Homed Name Resolution (Windows): Sends DNS queries outside the VPN tunnel
• Network Location Awareness (Windows): Can expose your real IP during network transitions

6. VPN Protocol Vulnerabilities

Older or poorly implemented VPN protocols can have security vulnerabilities that allow IP leaks:

• PPTP: Deprecated protocol with known security flaws (avoid entirely)
• L2TP/IPsec: Can leak under certain configurations
• IKEv2: Generally secure but can leak during reconnection if not properly implemented

Types of IP Leaks

IP leaks come in several forms, each with different implications:

1. IPv4 Leaks

Your traditional IPv4 address (e.g., 203.0.113.45) is exposed. This is the most common and serious type of IP leak, as IPv4 is still the primary protocol used by most websites and services.

2. IPv6 Leaks

Your IPv6 address (e.g., 2001:db8::1) is exposed while your IPv4 remains hidden. This is increasingly common as more ISPs adopt IPv6, but many VPNs haven't fully implemented IPv6 support.

3. DNS Leaks

While technically different from IP leaks, DNS leaks are closely related. A DNS leak occurs when your DNS queries (requests to translate website names like "google.com" into IP addresses) are sent to your ISP's DNS servers instead of your VPN's, revealing which websites you visit.

Learn more: We have a detailed guide on the differences between DNS, IP, and WebRTC leaks.

4. WebRTC Leaks

WebRTC (Web Real-Time Communication) is a browser technology that enables real-time communication (video calls, file sharing) directly between browsers. Unfortunately, WebRTC can expose your real IP address even when using a VPN, because it uses special network protocols (STUN/TURN servers) to establish direct peer-to-peer connections.

The problem: Your browser can make WebRTC requests that bypass the VPN tunnel entirely, leaking your local IP address to websites.

Why IP Leaks Are Dangerous

IP leaks undermine the core purpose of using a VPN and create several serious privacy and security risks:

1. Location Tracking

Your IP address reveals your approximate geographic location (usually accurate to your city or neighborhood). Websites, advertisers, hackers, and government agencies can use this to:

• Track your physical location
• Build a profile of your movements and activities
• Serve location-targeted advertising
• Implement geo-blocking or censorship

2. ISP Monitoring

When your IP leaks, your Internet Service Provider can see your internet activity. This means:

• Your ISP knows which websites you visit
• They can throttle your connection based on activity (e.g., streaming, torrenting)
• They can sell your browsing data to advertisers (legal in many countries)
• They must comply with government data retention and surveillance laws

3. Identity De-anonymization

Your IP address is directly linked to your ISP account, which contains your real name, address, and payment information. IP leaks can connect your online activities to your real-world identity:

• Copyright holders can identify torrent users
• Government agencies can track activists, journalists, or whistleblowers
• Hackers can target you with location-specific attacks
• Websites can build comprehensive profiles across your sessions

4. Bypassing Geo-Restrictions Fails

If you're using a VPN to access geo-restricted content (e.g., streaming services in other countries), an IP leak defeats this purpose:

• Streaming services (Netflix, BBC iPlayer, Hulu) detect your real location and block access
• Websites display content based on your actual location, not your VPN server's location
• You can't reliably bypass censorship in restrictive countries

5. Security Vulnerabilities

Knowing your real IP address makes you vulnerable to targeted attacks:

• DDoS attacks: Attackers can overwhelm your home internet connection
• Port scanning: Hackers can probe your network for vulnerabilities
• Phishing: Scammers can create location-specific phishing attacks
• Swatting: Malicious actors can use your location for dangerous pranks

How to Detect IP Leaks

Detecting IP leaks is straightforward with the right tools. Here's how to check if your VPN is leaking your IP address:

Step 1: Check Your Real IP Address (Without VPN)

Before connecting to your VPN, visit an IP checking website to record your real IP address:

1. Disconnect from your VPN (if connected)
2. Visit dovpn.com/ip-leak-test
3. Note your displayed IP address, ISP, and location

Step 2: Connect to Your VPN

Connect to your VPN service and choose a server in a different country (e.g., if you're in the US, connect to a server in Germany, UK, or Netherlands).

Step 3: Test for IP Leaks

While connected to your VPN, visit an IP leak test tool:

1. Go to dovpn.com/ip-leak-test
2. The tool will automatically check for:
   • IPv4 leaks
   • IPv6 leaks
   • DNS leaks
   • WebRTC leaks
3. Review the results

Step 4: Interpret the Results

✅ No Leaks (Good):

• The displayed IP address matches your VPN server's location (not your real location)
• The ISP shown is your VPN provider (not your actual ISP)
• No IPv6 address is shown (or it shows your VPN's IPv6 address)
• DNS servers belong to your VPN provider

❌ IP Leak Detected (Bad):

• Your real IP address is visible
• Your actual ISP is displayed
• Your true location is shown
• Multiple IP addresses appear (mixing your real IP and VPN IP)

Additional Testing Tips

• Test multiple times: IP leaks can be intermittent, so test several times over a few minutes
• Test different VPN servers: Some servers may leak while others don't
• Test during reconnection: Manually disconnect and reconnect your VPN to test for reconnection leaks
• Test with different protocols: Try OpenVPN, WireGuard, IKEv2, etc., to see if protocol affects leaks

How to Prevent IP Leaks

Preventing IP leaks requires both choosing the right VPN service and configuring your system correctly:

1. Choose a VPN with Built-In Leak Protection

Not all VPNs are created equal. Choose a VPN service that specifically protects against IP leaks:

• IPv6 leak protection: The VPN should either support IPv6 routing or completely block IPv6 traffic
• DNS leak protection: Built-in DNS servers that route all DNS queries through the VPN tunnel
• WebRTC leak protection: Browser-level WebRTC blocking or mitigation
• Kill switch: Automatically blocks all internet traffic if the VPN disconnects
• Automatic reconnection: Immediately reconnects if the VPN drops, minimizing exposure

2. Enable the VPN Kill Switch

The kill switch is your most important protection against IP leaks.

Most quality VPN apps include a kill switch feature (sometimes called "Network Lock" or "Internet Kill Switch"). This feature:

• Monitors your VPN connection status
• Immediately blocks all internet traffic if the VPN disconnects
• Prevents any data from leaking outside the VPN tunnel
• Automatically unblocks traffic when the VPN reconnects

How to enable: Check your VPN app's settings for "Kill Switch," "Network Lock," or "Internet Kill Switch" and enable it. The exact location varies by VPN provider.

3. Disable IPv6

If your VPN doesn't fully support IPv6, the safest option is to disable IPv6 entirely on your device:

Windows 10/11:

1. Open Control Panel → Network and Internet → Network Connections
2. Right-click your active network connection → Properties
3. Uncheck "Internet Protocol Version 6 (TCP/IPv6)"
4. Click OK

macOS:

1. Open System Preferences → Network
2. Select your active connection → Advanced
3. Go to TCP/IP tab
4. Set "Configure IPv6" to "Link-local only" or "Off"
5. Click OK → Apply

Linux:

sudo sysctl -w net.ipv6.conf.all.disable_ipv6=1
sudo sysctl -w net.ipv6.conf.default.disable_ipv6=1

4. Use OpenVPN or WireGuard Protocols

Stick to modern, secure VPN protocols:

• WireGuard: Modern, fast, and secure protocol with built-in leak protection
• OpenVPN: Well-tested, open-source protocol with strong security (use UDP for better performance)

Avoid: PPTP (obsolete and insecure), L2TP/IPsec (can leak), and SSTP (Windows-only, proprietary)

5. Disable Split Tunneling (If Not Needed)

If you don't specifically need split tunneling, disable it to ensure all traffic routes through the VPN. Check your VPN app's settings and turn off any "Split Tunnel," "Bypass VPN," or similar features.

6. Block WebRTC in Your Browser

WebRTC leaks occur at the browser level. Prevent them by:

• Chrome/Edge: Install the WebRTC Leak Prevent extension
• Firefox: Type about:config in the address bar, search for media.peerconnection.enabled, and set it to false
• Safari: Go to Preferences → Advanced → Show Develop menu, then Develop → WebRTC → Disable Legacy WebRTC API

7. Configure DNS Manually (Advanced)

For extra protection, configure your device to use your VPN provider's DNS servers:

• Use your VPN provider's recommended DNS servers (check their documentation)
• Or use privacy-focused public DNS: Cloudflare (1.1.1.1), Quad9 (9.9.9.9), or DNS.Watch (84.200.69.80)

Fixing IP Leaks: Step-by-Step Guide

If you've detected an IP leak, follow this systematic troubleshooting process:

Step 1: Verify the Leak Is Real

1. Test multiple times using our IP leak test tool
2. Try different VPN servers (different locations, different protocols)
3. Restart your VPN app and test again

Step 2: Enable Kill Switch

1. Open your VPN app settings
2. Find "Kill Switch," "Network Lock," or similar option
3. Enable it and reconnect to the VPN
4. Test again for leaks

Step 3: Disable IPv6

1. Follow the IPv6 disabling instructions above for your operating system
2. Restart your device
3. Reconnect to your VPN
4. Test for IPv6 leaks

Step 4: Switch VPN Protocols

1. In your VPN app settings, find "Protocol" or "Connection" settings
2. Try these protocols in order:
   • WireGuard (if available)
   • OpenVPN UDP
   • OpenVPN TCP
   • IKEv2
3. Test after each protocol change

Step 5: Disable WebRTC

1. Install WebRTC blocking extensions (see prevention section above)
2. Or disable WebRTC in Firefox via about:config
3. Test for WebRTC leaks specifically

Step 6: Disable Split Tunneling

1. Check your VPN app for "Split Tunnel" or "Bypass" settings
2. Disable any split tunneling features
3. Ensure all apps route through the VPN
4. Reconnect and test

Step 7: Update Your VPN Software

1. Check for VPN app updates (many bugs are fixed in newer versions)
2. Update to the latest version
3. Restart the app and reconnect
4. Test again

Step 8: Contact VPN Support or Switch Providers

If none of the above fixes work:

1. Contact your VPN provider's support team with your leak test results
2. Ask for specific configuration recommendations
3. If leaks persist, consider switching to a VPN with better leak protection

Frequently Asked Questions

What is an IP leak?

An IP leak occurs when your real IP address is exposed to websites or services despite using a VPN. This happens when your internet traffic bypasses the VPN tunnel, revealing your actual location and identity to third parties.

How do I know if my VPN is leaking my IP?

Use an IP leak test tool to check if your real IP address is visible. Connect to your VPN, then visit dovpn.com/ip-leak-test. If the displayed IP matches your ISP's IP instead of your VPN server's IP, you have an IP leak.

Can IP leaks happen even with premium VPNs?

Yes, even paid VPN services can experience IP leaks due to software bugs, configuration errors, kill switch failures, or protocol issues. Regular testing is recommended regardless of which VPN you use.

What's the difference between IP leaks and DNS leaks?

IP leaks expose your real IP address, revealing your location and ISP. DNS leaks expose your DNS queries (which websites you visit) to your ISP or third parties. Both compromise privacy but in different ways. Read our detailed comparison guide to learn more.

How do I fix an IP leak?

To fix IP leaks: 1) Ensure your VPN is properly connected, 2) Enable the VPN kill switch, 3) Disable IPv6 if your VPN doesn't support it, 4) Check for split tunneling settings, 5) Update your VPN software, and 6) Switch VPN protocols (try WireGuard or OpenVPN).

Are IP leaks dangerous?

Yes, IP leaks can be dangerous as they expose your real location, ISP, and potentially your identity to websites, advertisers, hackers, or government agencies. This defeats the purpose of using a VPN and can compromise your privacy and security.

Do free VPNs leak your IP address more often?

Yes, free VPNs are significantly more likely to leak your IP address. They often lack proper leak protection features, use outdated protocols, and have fewer resources for maintenance and security updates. Additionally, some free VPNs intentionally leak data or inject tracking as part of their business model.

Can I prevent IP leaks on mobile devices?

Yes, but it requires extra care. Enable your VPN's kill switch, disable IPv6 on your mobile device, and use your VPN provider's official app rather than manual configurations. Test regularly using mobile-friendly leak test tools.

Conclusion: Stay Leak-Free

IP leaks are a serious privacy concern that can completely undermine your VPN's protection. Understanding what causes IP leaks, how to detect them, and how to prevent them is essential for anyone relying on VPNs for privacy, security, or accessing geo-restricted content.

Key takeaways:

• IP leaks expose your real IP address despite using a VPN
• They can happen due to IPv6 issues, kill switch failures, WebRTC vulnerabilities, or VPN bugs
• Regular testing is essential — test your VPN weekly or after any software updates
• Enable kill switch, disable IPv6, and use modern protocols (WireGuard, OpenVPN)
• Choose VPN providers with proven leak protection and transparent security practices

Test Your VPN for IP Leaks Now

Don't wait until your privacy is compromised. Test your VPN right now to ensure it's protecting you properly.

Need a VPN That Doesn't Leak?

If your current VPN is leaking your IP address, it's time to switch to a provider with proven leak protection. Check out our comprehensive reviews of VPNs with built-in leak prevention: