WebRTC Proxy Leak Detection

WebRTC (Web Real-Time Communication) is a technology that enables real-time communication directly between web browsers without requiring plugins. It's commonly used for video calls, voice chat, and peer-to-peer file sharing.

How WebRTC Works

• Peer-to-Peer: Creates direct connections between browsers
• STUN/TURN Servers: Help establish connections through NAT and firewalls
• ICE Candidates: Discover available network paths and IP addresses
• Media Streams: Transmit audio, video, and data directly

While WebRTC is excellent for real-time communication, it can expose your real IP address even when using a VPN or proxy, making it a privacy concern.

WebRTC can leak your real IP address through the ICE (Interactive Connectivity Establishment) candidate gathering process:

Types of IP Leaks

• Local IP Leak: Reveals your private network IP (192.168.x.x, 10.x.x.x)
• Public IP Leak: Exposes your real public IP address, bypassing VPN/proxy
• IPv6 Leak: Many VPNs only tunnel IPv4, leaving IPv6 exposed

Why This Happens

WebRTC operates at the browser level and creates direct peer-to-peer connections. These connections bypass the proxy/VPN tunnel configured at the system or application level.

Privacy Implications

• Websites can detect your real location despite VPN usage
• Your actual ISP and network configuration can be identified
• Can be used for fingerprinting and tracking purposes
• Defeats the anonymity provided by proxies and VPNs

There are several methods to prevent WebRTC from leaking your real IP address:

Browser Extensions

• uBlock Origin: Disable WebRTC in advanced settings
• WebRTC Leak Prevent: Chrome extension specifically for WebRTC protection
• NoScript: Disable WebRTC along with other JavaScript features

Browser Settings

• Firefox: Set media.peerconnection.enabled to false in about:config
• Chrome/Edge: Use chrome://flags to disable WebRTC or install an extension
• Brave: Built-in WebRTC leak protection in privacy settings
• Tor Browser: WebRTC is disabled by default

VPN Configuration

• Choose a VPN that includes WebRTC leak protection
• Ensure IPv6 is disabled or tunneled through the VPN
• Use a VPN with a built-in kill switch
• Test regularly using tools like this one

For Web Scraping

If you're using browser automation for web scraping:

• Puppeteer/Playwright: Disable WebRTC via browser launch flags
• Selenium: Configure browser preferences to disable WebRTC
• Scrapfly: Automatic WebRTC protection with ASP enabled

This tool tests for WebRTC leaks by creating a connection to a TURN server and examining the IP addresses revealed during the ICE candidate gathering process.

Test Components

• Public IP: Your IP address as seen by our server
• WebRTC Client Side IP Offer: IP address revealed by WebRTC in your browser
• WebRTC TURN Feedback: IP address that connected to our TURN server

Possible Results

What to Do If a Leak is Detected

1. Disable WebRTC in your browser settings or use an extension
2. Switch to a VPN provider with built-in WebRTC leak protection
3. Use a browser with WebRTC protection (Brave, Tor Browser)
4. Test again after implementing protection measures

If you're using browser automation for web scraping, WebRTC can reveal your automation infrastructure and lead to blocking. Scrapfly provides automatic WebRTC protection.

Why WebRTC Matters for Web Scraping

• Anti-bot systems use WebRTC fingerprinting to detect automation
• Your datacenter IP can be exposed even with residential proxies
• Consistent WebRTC fingerprints help identify bot traffic
• WebRTC can reveal that you're using headless browsers

Scrapfly's WebRTC Protection

from scrapfly import ScrapflyClient, ScrapeConfig

client = ScrapflyClient(key='YOUR_API_KEY')

result = client.scrape(ScrapeConfig(
    url='https://example.com',
    asp=True,  # Automatic WebRTC protection
    render_js=True,
    country='US'
))

print(result.content)  # WebRTC is properly handled!