GreenTunnel is an anti-censorship proxy utility that bypasses Deep Packet Inspection systems used by ISPs to block access to websites.
The tool addresses hostname-based blocking by running a local proxy that fragments TLS ClientHello packets so the target hostname never appears intact in a single packet, and routes DNS queries through encrypted channels to prevent resolver-based blocking or observation. This approach defeats DPI filtering without requiring a full VPN or hiding the user's IP address.
Developers should understand that GreenTunnel solves a specific problem: circumventing ISP-level hostname blocking in environments with DPI filtering. It suits users in regions where certain websites are blocked at the network level and who need lightweight, local proxy functionality rather than a full VPN solution. The tool is available as a CLI, a desktop application for macOS, Windows, and Linux, and a Docker image, making it accessible across different deployment scenarios. It is not a VPN and does not mask IP addresses.
The project underwent a complete TypeScript rewrite in version 3, reducing runtime dependencies significantly and implementing RFC 8484 DoH and DoT support alongside a system-proxy layer that persists settings across crashes. The maintainer has adopted an AI-assisted development model and requests contributors submit detailed prompts describing desired changes rather than pull requests, with the maintainer executing the prompts and crediting contributors in commit history. Small, focused pull requests for bug fixes and typos remain welcome.
