Devnettun

Devnettun is an open-source software framework designed to help developers create, test, and deploy distributed applications in user-space virtual networks. It provides a tun-based networking layer that enables virtual network overlays for development and testing environments, allowing isolated networks without altering host networking. The project aims to improve portability, reproducibility, and safety for networked software experiments.

The project emerged in the early 2020s as a community-driven effort to simplify local network emulation for developers. It emphasizes interoperability with common development tools, supports Linux and macOS with ongoing work for broader platform coverage, and offers both a command-line interface and a REST API to manage networks and workloads. Development follows an open governance model with contributions from individuals and organizations.

Core components of devnettun include a network core that manages virtual tunnels, a plugin system for protocol adapters, a sandboxed runtime for workloads, and a control plane for policy and access management. It supports containerized workloads, integrates with CI/CD pipelines, and provides observability hooks to monitor traffic, latency, and resource usage within simulated networks.

Typical use cases involve simulating complex network topologies for microservices and edge deployments, testing network resilience under latency or partition scenarios, and facilitating hands-on networking education for developers. The framework is designed to be deterministic for repeatable tests and to serve as a learning platform for software-defined networking concepts.

See also: virtual network, TUN/TAP, software-defined networking, container networking.