DNS vs IP vs WebRTC Leaks

VPN users often hear about IP leaks, DNS leaks, and WebRTC leaks, but many don't understand the critical differences between them. While all three compromise your privacy, they expose different information through different mechanisms — and require different fixes. This comprehensive guide explains each leak type, compares their severity, and shows you how to detect and prevent all three.

Quick Comparison: IP vs DNS vs WebRTC Leaks

IP Leaks Explained

What Is an IP Leak?

An IP leak occurs when your real IP address is exposed to websites, services, or third parties despite using a VPN. This is the most direct form of VPN failure — your VPN is supposed to hide your IP, but it's leaking through.

What Information Does an IP Leak Expose?

Your real IP address reveals:

• Geographic location: Usually accurate to your city or neighborhood
• ISP (Internet Service Provider): Who provides your internet connection (Comcast, Verizon, etc.)
• Organization: If using a business network, your company name may be visible
• Connection type: Residential, business, mobile, datacenter, etc.
• Approximate time zone

Analogy: Your IP address is like your home's street address. Even if it doesn't include your name, it shows exactly where you are, and your ISP knows who lives at that address.

How IP Leaks Happen

1. IPv6 leaks: Your VPN routes IPv4 but not IPv6 traffic
2. VPN connection drops: Temporary disconnections expose your real IP
3. Kill switch failures: Safety mechanism doesn't engage when VPN drops
4. Split tunneling misconfig: Some traffic intentionally bypasses VPN but leaks
5. VPN protocol vulnerabilities: Bugs in VPN software

Read more: Complete guide to IP leaks

Example Scenario: IP Leak

Situation: You're in New York, using Verizon as your ISP. You connect to a VPN server in London to access UK content.

✅ VPN working correctly:

• Websites see a London IP address
• ISP shown: Your VPN provider (e.g., M247 Europe)
• Location detected: London, UK

❌ IP leak detected:

• Websites see your real New York IP address
• ISP shown: Verizon
• Location detected: New York, NY, USA

Result: The UK website blocks you because it detects you're actually in the US. Your VPN has failed.

DNS Leaks Explained

What Is a DNS Leak?

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 DNS servers, even though you're connected to a VPN.

Understanding DNS (Domain Name System)

DNS is like the internet's phonebook. When you type "facebook.com," your device asks a DNS server "What's the IP address for facebook.com?" The DNS server responds with something like "157.240.241.35," and your device connects to that IP.

The privacy problem: Whoever runs the DNS server can see every website you query, creating a complete log of your browsing history.

What Information Does a DNS Leak Expose?

DNS leaks reveal:

• Every website you visit: Your complete browsing history
• When you visit them: Timestamps of each DNS query
• How often you visit: Frequency of queries to specific sites
• Your real location: Via the DNS server used (ISP DNS reveals your ISP)

Analogy: Imagine you're using a VPN to hide your activities, but every time you want to visit a website, you call your ISP and ask for directions. The VPN hides your address, but your ISP knows everywhere you're trying to go.

How DNS Leaks Happen

1. Operating system DNS preferences: Windows' Smart Multi-Homed Name Resolution sends DNS queries to all network interfaces
2. ISP DNS hijacking: Some ISPs intercept all DNS queries regardless of configuration
3. VPN app bugs: VPN doesn't properly configure DNS settings
4. Manual DNS configuration: You've set custom DNS that bypasses VPN
5. Transparent DNS proxies: Your ISP or router intercepts DNS traffic

Example Scenario: DNS Leak

Situation: You're connected to a VPN to hide your browsing from your ISP.

✅ VPN working correctly (no DNS leak):

• DNS queries go to your VPN provider's DNS servers
• Your ISP sees encrypted VPN traffic (can't see which websites you visit)
• Only your VPN provider knows your DNS queries

❌ DNS leak detected:

• DNS queries go to your ISP's DNS servers (8.8.8.8, 1.1.1.1, or ISP's DNS)
• Your ISP sees every website you visit via DNS logs
• Your VPN encrypts your connection, but your ISP knows WHERE you're connecting

Result: Your IP address may be hidden, but your ISP has a complete log of your browsing history. Your privacy is compromised.

WebRTC Leaks Explained

What Is a WebRTC Leak?

A WebRTC leak occurs when your web browser exposes your real IP address through WebRTC (Web Real-Time Communication) technology, even when you're connected to a VPN. This happens because WebRTC uses special protocols (STUN/TURN servers) to establish peer-to-peer connections that can bypass your VPN.

Understanding WebRTC

WebRTC (Web Real-Time Communication) is a browser technology that enables real-time audio, video, and data sharing directly between browsers without plugins. It powers:

• Video calling (Google Meet, Zoom web version, Discord)
• Screen sharing
• Peer-to-peer file transfers
• Live streaming

The privacy problem: To establish direct peer-to-peer connections, WebRTC needs to discover your device's real IP addresses (both local and public). It does this through STUN (Session Traversal Utilities for NAT) servers, which can expose your IP even when using a VPN.

What Information Does a WebRTC Leak Expose?

WebRTC leaks can reveal:

• Your local IP address: Your device's IP on your local network (e.g., 192.168.1.105)
• Your real public IP address: Your ISP-assigned IP (bypassing VPN)
• Your location: Via your real IP address
• Your ISP: Via your real IP address

Analogy: Imagine you're using a pseudonym (VPN) to hide your identity in a conversation. But when you want to make a video call, your phone number (WebRTC) is automatically shared with the other person, revealing your real identity.

How WebRTC Leaks Happen

1. Browser WebRTC enabled: Chrome, Edge, Firefox, Safari all have WebRTC enabled by default
2. STUN server requests: Websites use WebRTC to discover your real IP via STUN servers
3. VPN can't intercept: WebRTC requests happen at browser level, often bypassing VPN tunnel
4. JavaScript exploits: Websites run JavaScript that triggers WebRTC discovery

Example Scenario: WebRTC Leak

Situation: You're connected to a VPN and visit a website. The website runs JavaScript to check for WebRTC leaks.

✅ VPN working correctly (no WebRTC leak):

• WebRTC is disabled in your browser
• Or your VPN blocks WebRTC requests
• Website only sees your VPN IP address
• No local IP addresses are exposed

❌ WebRTC leak detected:

• Website runs WebRTC detection script
• Your browser responds with:
  • Local IP: 192.168.1.105 (your device's local address)
  • Public IP: 73.158.241.92 (your real ISP-assigned IP)
• Website now knows your real IP despite VPN showing different IP

Result: Your IP is exposed to the website. Trackers, advertisers, or malicious actors can correlate your real IP with your VPN IP, potentially de-anonymizing you.

Which Browsers Are Affected by WebRTC Leaks?

• Google Chrome: ✅ Affected (WebRTC enabled by default)
• Microsoft Edge: ✅ Affected (WebRTC enabled by default)
• Mozilla Firefox: ✅ Affected (can be disabled in about:config)
• Safari: ⚠️ Partially affected (newer versions have better protection)
• Brave: ✅ Protected (WebRTC blocking built-in)
• Tor Browser: ✅ Protected (WebRTC disabled by default)

Which Leak Type Is Most Dangerous?

The answer depends on your threat model and what you're trying to protect:

IP Leaks Are Most Critical For:

• Bypassing geo-restrictions: If your real IP shows, geo-blocking services (Netflix, BBC iPlayer) will block you
• Hiding your location: IP address reveals your city/region
• Avoiding targeted attacks: Hackers can DDoS or port scan your real IP
• Identity protection: Your IP is directly linked to your ISP account (with your real name and address)

Severity: Critical

DNS Leaks Are Most Dangerous For:

• Privacy from ISP: Your ISP can see and log every website you visit
• Censorship bypass: In restrictive countries, DNS queries reveal what you're accessing
• Avoiding profiling: DNS logs create a complete profile of your interests and activities
• Legal protection: Authorities can subpoena ISP DNS logs (common in copyright cases)

Severity: High (can be worse than IP leaks for long-term privacy)

WebRTC Leaks Are Most Concerning For:

• Anonymity: Websites can correlate your VPN IP with your real IP, breaking anonymity
• Tracking prevention: Advertisers use WebRTC to track you across sessions
• Browser-level privacy: Exposes your local network configuration

Severity: Medium-High (less severe than IP/DNS leaks but still compromises privacy)

The Verdict: Which Is Worst?

For most users: DNS leaks are the biggest long-term privacy threat.

Here's why:

• DNS leaks are very common (more common than IP leaks)
• They expose your complete browsing history (not just your location)
• They're harder to detect (your VPN might "work" but DNS still leaks)
• ISPs actively log DNS queries (and can be compelled to share with authorities)
• Many users don't realize they're leaking

However: For bypassing geo-restrictions or immediate identity protection, IP leaks are most critical because they directly expose your location and defeat VPN purpose.

How to Detect Each Leak Type

Testing for All Three Leaks at Once

The easiest method is using a comprehensive leak test tool:

1. Connect to your VPN
2. Visit dovpn.com/ip-leak-test
3. The tool automatically checks:
   • IPv4 leaks
   • IPv6 leaks
   • DNS leaks
   • WebRTC leaks
4. Review results

Manual Testing for Specific Leak Types

Testing for IP Leaks:

1. Note your real IP before connecting to VPN
2. Connect to VPN in a different country
3. Visit dovpn.com/ip-leak-test
4. Check if IP shows VPN location or your real location

Testing for DNS Leaks:

1. Connect to VPN
2. Visit dovpn.com/ip-leak-test
3. Check DNS servers section
4. If you see your ISP's DNS servers, you have a DNS leak

Testing for WebRTC Leaks:

1. Connect to VPN
2. Visit dovpn.com/ip-leak-test
3. Check WebRTC section
4. If it shows your local IP or real public IP, you have a WebRTC leak

How to Fix All Three Leak Types

Fixing IP Leaks

1. Enable VPN kill switch: Blocks internet if VPN disconnects
2. Disable IPv6: If VPN doesn't support IPv6, turn it off in OS settings
3. Use modern protocols: WireGuard or OpenVPN
4. Disable split tunneling: Unless specifically needed
5. Update VPN app: Bug fixes often address leak issues

Platform-specific guides:

• Windows IP leak fixes
• Mac IP leak fixes
• iPhone IP leak fixes

Fixing DNS Leaks

1. Enable VPN DNS protection: Check VPN app settings for "DNS leak protection"
2. Manually set DNS servers: Use VPN provider's DNS or privacy-focused DNS (Cloudflare: 1.1.1.1, Quad9: 9.9.9.9)
3. Disable Smart Multi-Homed Name Resolution (Windows): Registry edit to prevent DNS queries to multiple interfaces
4. Flush DNS cache: Clear cached DNS entries that may leak
5. Use DNS over HTTPS (DoH): Encrypts DNS queries at browser level

Fixing WebRTC Leaks

Chrome/Edge:

1. Install WebRTC Leak Prevent extension

Firefox:

1. Type about:config in address bar
2. Search media.peerconnection.enabled
3. Toggle to false

Safari:

1. Preferences → Advanced → Show Develop menu
2. Develop → WebRTC → Disable Legacy WebRTC API

Comprehensive Protection: All Three Leaks

For complete privacy, implement all fixes:

1. Choose a VPN with comprehensive leak protection: Built-in kill switch, DNS leak protection, IPv6 blocking
2. Configure your OS: Disable IPv6, set VPN DNS manually
3. Configure your browser: Disable WebRTC or install blocking extensions
4. Test regularly: Weekly testing ensures leaks haven't returned

Frequently Asked Questions

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

IP leaks expose your real IP address (revealing your location and ISP), while DNS leaks expose your DNS queries (revealing which websites you visit). IP leaks show WHERE you are; DNS leaks show WHAT you're doing online.

Which is worse: IP leak, DNS leak, or WebRTC leak?

IP leaks are generally most critical as they expose your identity and location. However, DNS leaks can be worse for privacy since they reveal your complete browsing history to your ISP. WebRTC leaks are typically less severe but still compromise privacy. Ideally, prevent all three.

Can you have an IP leak without a DNS leak?

Yes, leaks can occur independently. You might have an IP leak while your DNS is protected, or vice versa. You can also experience multiple leak types simultaneously. This is why comprehensive leak testing is important.

How do I test for all three leak types at once?

Use a comprehensive leak test tool like dovpn.com/ip-leak-test that checks IP leaks (IPv4 and IPv6), DNS leaks, and WebRTC leaks simultaneously. Connect to your VPN first, then run the test.

Do I need to fix all three types of leaks?

Yes, for complete privacy protection you should fix IP leaks, DNS leaks, AND WebRTC leaks. Each leak type exposes different information about you, and comprehensive VPN protection requires blocking all three.

Can free VPNs prevent all three leak types?

Most free VPNs do NOT properly prevent all leak types. They often lack kill switches, DNS leak protection, and IPv6 support. Free VPNs frequently have DNS leaks and may intentionally leak data as part of their business model. Use reputable paid VPNs for comprehensive protection.

Which leak type is hardest to detect?

DNS leaks are hardest to detect because your VPN appears to be working (your IP is hidden), but your DNS queries are leaking to your ISP. Many users don't realize they have DNS leaks because they only check their IP address.

Conclusion: Comprehensive Leak Protection

Understanding the differences between IP leaks, DNS leaks, and WebRTC leaks is essential for comprehensive VPN privacy. Each leak type exposes different information through different mechanisms, and proper protection requires addressing all three.

Key takeaways:

• IP leaks expose your location and identity (critical for geo-unblocking)
• DNS leaks expose your complete browsing history (critical for ISP privacy)
• WebRTC leaks expose your real IP via browser (critical for anonymity)
• All three can occur simultaneously or independently
• Comprehensive testing is essential — test regularly
• Quality VPNs provide protection against all three leak types

Need a VPN That Prevents All Three Leak Types?

Choose a VPN with comprehensive leak protection — built-in kill switch, DNS leak protection, IPv6 blocking, and WebRTC mitigation: