Follow the White Rabbit: Writing a VPN in Rust and Finding a Way Out of Your Own Tunnel

The author shares their experience developing a custom VPN service called PAYPHONE using the Rust programming language. The article details the process of creating a network tunnel, including protocol implementation and troubleshooting technical challenges. The author discusses issues encountered during development, ranging from packet looping within the tunnel to timer malfunctions and incorrect process termination signal handling. This article provides a technical breakdown with code snippets, which will be useful for developers interested in network programming and low-level VPN implementation. The author also shares practical tips for debugging and fixing errors discovered after the first successful connection, emphasizing the importance of a deep understanding of network protocols when building such tools from scratch.