# OpenTether – Experimental IPv4 TCP-over-USB test tool [](https://ko-fi.com/W3T61ZU5FS)

OpenTether is an experimental personal-use IPv4 TCP routing test that uses an Android SOCKS5 proxy exposed over ADB and a Wintun/tun2socks path on Windows.

How it works

• Android app runs a TCP-only SOCKS5 proxy on port 1080.
• Windows desktop uses ADB to forward that port to localhost.
• tun2socks + wintun.dll create a virtual network adapter.
• A low-metric IPv4 default route sends traffic through the adapter.
• The desktop script validates route selection and performs a TLS-authenticated HTTPS test.

Current limitations

• IPv4 TCP only – IPv6, UDP, and other protocols are not handled.
• IPv6 traffic will leak unless you disable IPv6 on physical adapters.
• DNS behavior depends on Windows interface selection and policies.
• Hard process termination (Task Manager) may leave routes behind.
• Android app is a basic SOCKS5 proxy – no VpnService, no UDP ASSOCIATE.

For testing only

This is not a polished commercial product. It is meant for developers who want to understand and control their tethering stack. Use at your own risk.

Build & run

1. Push the repository to GitHub.
2. Download the OpenTether-APK and OpenTether-Desktop artifacts from Actions.
3. Install the APK, enable USB debugging, plug in your phone.
4. Run OpenTetherRouter.exe as Administrator.
5. Monitor the console – it will show the egress IP after successful connection.

License

MIT