Nebula

Nebula is a scalable overlay networking tool that connects computers anywhere in the world, focusing on performance, simplicity, and security. It can link a handful of machines or tens of thousands, across cloud providers, datacenters, and endpoints, without a fixed addressing scheme. It runs on Linux, Windows, macOS, FreeBSD, iOS, and Android.

Nebula is a mutually authenticated peer-to-peer network built on the Noise Protocol Framework. Certificates assert each node's IP address, name, and group membership, and user-defined groups drive provider-agnostic traffic filtering between nodes. Discovery nodes called lighthouses let peers find each other and use UDP hole punching to connect through most firewalls and NATs.

The nebula-cert tool creates a certificate authority and signs host certificates; each node runs from a YAML config file. By default it uses ECDH with AES-256-GCM and Curve25519, with an optional NIST P-256 curve and BoringCrypto builds for compliance needs.