Configured a proxy but an IP test still shows your real IP? WebRTC may be leaking it. This guide explains Replace, Forward, Real, Disabled, and Proxy UDP modes in fingerprint browsers, their trade-offs, how to choose by scenario, and how to verify the configuration.
Have you ever configured a proxy for your browser, only to open an IP-checking site and still see your real address? The issue may be a WebRTC leak.
WebRTC (Web Real-Time Communication) lets browsers handle audio and video calls without plugins, but when establishing a connection it may bypass the proxy and expose your device’s real IP. Video meetings, voice chat, online customer service, and even unnoticed page scripts can invoke it. This guide explains the available WebRTC modes in fingerprint browsers such as PurpleMark, their trade-offs, and how to choose and verify them.
1. The 5 WebRTC Configuration Modes
Multi-account fingerprint browsers usually provide several WebRTC handling options under environment fingerprint settings. The five common modes are:
1. Replace — the default choice for most scenarios When a webpage initiates a WebRTC request, the browser returns the proxy IP configured for that environment and hides the local real IP, keeping the “proxy IP” consistent with the “IP seen by WebRTC.” It works well for routine account operations on Amazon, TikTok, Shopify, Facebook, and similar platforms, and is usually the best mode to try first.
2. Forward — an advanced alternative to Replace WebRTC requests are relayed through public STUN servers so the request path looks as though it comes from a normal network node rather than from simple value replacement. It can be harder to detect than Replace mode and is suitable for platforms with stricter source-connection validation, such as some transaction or payment sites.
3. Real — no intervention The browser uses the device’s actual physical IP without modification. This is normally appropriate only for cases that explicitly require a real network environment, such as network testing or local development and debugging. It generally should not be enabled for scaled operations that depend on environment isolation.
4. Disabled — block WebRTC at the source The browser’s WebRTC capability is turned off entirely, so websites cannot initiate WebRTC requests and this type of leak is eliminated at the source. The trade-off is that sites relying on camera or voice features, such as web voice calling or online customer support, may stop working. It suits scenarios with high privacy requirements that do not depend on browser-based audio/video communication.
5. Proxy UDP (Disable UDP) — lower-level protocol control WebRTC primarily uses UDP for transport. Enabling this option restricts communication to TCP and reduces the possibility of discovering the real route through UDP-port probing. It is suitable for environments that need to handle stricter network checks.
2. Which Mode Should You Choose for Each Scenario?
| Your need | Recommended mode | Why |
|---|---|---|
| Maximum privacy, no browser audio/video needed | Disabled | Eliminates WebRTC leaks at the source |
| Need WebRTC features + IP protection | Proxy UDP (Disable UDP) | Keeps necessary functionality while blocking UDP probing |
| Routine multi-account operations, avoid IP inconsistency | Replace | Keeps proxy IP and WebRTC IP consistent while balancing realism and stability |
| Platforms with strict source validation | Forward | Uses STUN relay for a more natural connection path |
In general, start with Replace mode for most scenarios. If you encounter stricter connection audits or sites that depend on voice features, switch to Forward or Disable UDP as needed.
3. Where Do You Configure It, and How Do You Verify It?
Configuration location: Create or edit a browser environment in the fingerprint browser, open the “Fingerprint Settings” (fingerprint parameters) section, and select the desired WebRTC mode. Also make sure the environment has a proxy configured correctly so traffic goes through the intended proxy server instead of connecting directly to the public internet.
Verification method: After saving the settings and opening the environment, visit a WebRTC leak-test tool. Check whether the IP it shows matches the proxy IP configured for that environment and whether your local real IP appears. If the displayed IP matches the proxy and no real address is exposed, the configuration is working.
4. Frequently Asked Questions
Why can accounts still be linked even when a proxy is in use? A WebRTC leak may be the reason. WebRTC can bypass the proxy and expose the device’s real physical IP to the site. Selecting an appropriate WebRTC mode in the fingerprint browser can block this type of leak.
Will Disabled mode affect normal browsing? It can affect browser features that depend on web audio/video or voice. If you do not need those capabilities, Disabled mode provides the strongest privacy. If you do need them, use Replace or Forward instead.
Summary
WebRTC is a common reason a real IP can still leak even after a proxy is configured. The five modes offered by fingerprint browsers — Replace, Forward, Real, Disabled, and Proxy UDP — are essentially different trade-offs between privacy and functionality: start with Replace by default, use Forward for stricter audits, disable WebRTC when audio/video is unnecessary, and disable UDP when needed. After choosing a mode, run a leak test and confirm that the displayed IP matches the proxy IP before considering the setup complete.
