ZeroTier is a highly secure software defined networking service (SDN) that allows peer to peer connections between device over the internet. We use it to allow our engineers to request permission to view our client's screens access whenever they ask for help.
Installing it is easy. Download and run the installer below.
During the installation, you may see a System Extension Blocked popup. If you do, click Open Security Preferences, then click Allow in the bottom right of the System Preferences window.