danterolle/tund

TunD is a small tool that creates a virtual LAN, a private network that makes computers in different physical locations behave as if they were plugged into the same local network. It was built mainly for LAN party style gaming, unreliable home networks, or playing games directly with friends over the internet using IP addresses. One machine runs TunD in server mode, and every other machine connects to it as a client. Once connected, clients automatically discover one another and get a virtual IP address in a private range, such as 10.9.0.2. Traffic between clients is tunneled through the server over UDP, and the connection is encrypted between each client and the server, though the server itself can still see the traffic since it needs to route it. The project explains that it is deliberately narrower than tools like WireGuard, Tailscale, or ZeroTier. Those handle general purpose secure networking, while TunD focuses specifically on giving games and similar software a fixed private subnet with automatic peer discovery and broadcast support, without needing accounts or an external service. TunD is written in C so it can talk directly to low level networking pieces like UDP sockets and TUN devices, and it works on Windows, macOS, and Linux, using Wintun for TUN support on Windows. There is also an optional Flutter based desktop app for people who prefer a graphical launcher over the command line interface. The author notes that AI assistance was used during development, more heavily for the Flutter GUI portion than for the C networking core. Getting started involves generating a random shared key, running the tool in server mode on one machine with administrator or root privileges, and then connecting other machines as clients using that same key. Pre-built binaries are available on the releases page, and the project is released under the MIT license.