ZeroTier One
ZeroTierOne is the open source ethernet switch for the ZeroTier network. It is a way to connect devices over private networks anywhere in the world. Its done by creating a network and then joining two or more devices to that network.
Example config
services.zerotierone = {
enable = true;
joinNetworks = [
"6465f4ee45356976"
"71e441cc137b93c8"
];
};