Design and Implementation of a Secure Peer-to-Peer Mesh VPN with NAT Traversal and Relay-Based Connectivity

Virtual Private Networks (VPNs) are widely used to provide secure communication between distributed devices. Traditional VPN solutions typically rely on centralized gateways, introducing performance bottlenecks and single points of fail-ure. Modern mesh VPN architectures address these limitations through direct peer-to-peer communication, dynamic routing, and secure endpoint discovery. This paper presents a peer-to-peer mesh VPN system designed to provide secure, scalable, and efficient communication across heterogeneous networks. The pro-posed architecture combines WireGuard-based tunneling, public-key cryptography, STUN and ICE-based NAT traversal, and relay fallback mechanisms inspired by modern mesh network-ing systems. This enables automatic peer discovery, encrypted communication, dynamic route establishment, and reliable con-nectivity even when direct peer-to-peer communication is not feasible. Experimental evaluation demonstrates throughput of up to 1.2 Gbps with 17 ms latency on local networks, 122 Mbps with 227 ms latency across geographically separated networks, and 21 Mbps with 435 ms latency through relay-assisted communication. The proposed system offers a practical framework for secure de-centralized networking while maintaining simplicity, scalability, and high performance.