WA

Case Study ยท Public Source

TrueTunnel VPN

Native C++23 Windows networking software spanning virtual adapters, encrypted transport, packet framing, routing and NAT integration, GUI control, and multi-client behavior.

Problem

VPN software crosses several difficult systems boundaries at once: virtual network adapters, packet framing, encryption, transport behavior, Windows routing, NAT, concurrency, user controls, and build reproducibility. The project makes those boundaries explicit and testable.

Architecture

The native client and server use Wintun and Winsock to move IP packets over encrypted TCP or UDP transports. Windows routing and NAT integration connect the tunnel to the host network, while a Direct3D/ImGui interface exposes configuration and runtime state without replacing the underlying service logic.

Engineering constraints

  • Handle multiple clients without mixing packet state or connection lifecycle.
  • Support encrypted TCP and UDP transport paths behind a consistent tunnel interface.
  • Coordinate virtual-adapter, routing, NAT, and privilege-sensitive Windows behavior.
  • Keep the GUI separate from packet-processing and connection-management concerns.
  • Validate multiple cipher and transport combinations through integration testing.

Technologies

C++23 Windows Wintun Winsock OpenSSL Encrypted TCP / UDP Windows Routing / NAT Direct3D / ImGui CMake Integration Testing

Outcome

TrueTunnel is a public example of hands-on C++ systems work: not only network algorithms, but the operating-system integration, lifecycle handling, controls, and repeatable testing needed to make them useful.