Using proxies with anti-detect browsers can lead to real IP address leaks if the software lacks proper UDP support. While many standard proxies only handle TCP traffic, modern web protocols like HTTP/3 and technologies such as WebRTC rely heavily on UDP for performance and real-time communication.
The risk arises when a browser attempts to establish a connection via UDP that bypasses the proxy. In the case of WebRTC, the Interactive Connectivity Establishment (ICE) mechanism may discover and use a direct path to the user's real network interface, exposing the actual IP address to the target site.
Furthermore, the QUIC protocol, which powers HTTP/3, is designed to survive network changes. If a proxy connection is interrupted, the browser may attempt to restore the session directly through the user's real network interface, creating a potential security vulnerability.
Many anti-detect solutions address this by simply disabling WebRTC or forcing a fallback to HTTP/2. However, these methods can trigger anti-fraud systems due to unusual network behavior or inconsistent protocol usage, which may negatively impact a user's fraud score.
True UDP support requires control at the operating system's network stack level, often involving virtual network interfaces or deep socket interception. This ensures all traffic is forced through a tunnel, preventing applications from detecting the user's real hardware or network path.
