How It Works
[Android Device]
│
│ OpenVPN TCP/UDP
▼
[SNI Tunnel Client] ← Wraps traffic in SSL + injects fake SNI
│
│ Looks like: HTTPS → microsoft.com ✓
▼
[ISP Firewall] ← Passes through — sees only valid HTTPS
│
▼
[VPS Server] ← Decrypts TLS, recovers OpenVPN traffic
│
▼
[OpenVPN Server] ← Receives native OpenVPN traffic
│
▼
Internet
The core trick is SNI injection: the tunnel client inserts a trusted domain name (e.g. microsoft.com) into the TLS handshake. The ISP sees what appears to be a standard HTTPS connection and allows it through. The VPS server on the other end strips the SSL wrapper and forwards the real OpenVPN packets to the OpenVPN server.