**ZeroTier** is a smart programmable VPN *(Virtual Private/Public Network)* that acts as an Ethernet switch for planet Earth. It allows all
networked devices, VMs, containers, and applications to communicate as if they
all reside in the same physical data center or cloud region.

This is accomplished by combining a cryptographically addressed and secure peer
to peer network (termed VL1) with an Ethernet emulation layer somewhat similar
to VXLAN (termed VL2). Our VL2 Ethernet virtualization layer includes advanced
enterprise SDN features like fine grained access control rules for network
micro-segmentation and security monitoring.

All ZeroTier traffic is encrypted end-to-end using secret keys that only you
control. Most traffic flows peer to peer, though we offer free (but slow)
relaying for users who cannot establish peer to peer connections.

The goals and design principles of ZeroTier are inspired by among other things
the original Google BeyondCorp paper and the Jericho Forum with its notion of
"deperimeterization."