Tailscale
Tailscale Inc. is a software company with a freemium business model based in Toronto, Canada. It was founded in 2019 and is headquartered on Ontario. Tailscale provides an open-source software defined mesh virtual private network (VPN) software and a web-based management service. The company provides a zero config mesh VPN service under the same name. In November 2020 the company secured funding of $12 million in a Series A round. The investment is lead by Accel with Heavybit's and Uncork Capital's participation. Software. The open-source software acts in combination with the management service  to esablish peer-to-peer or relayed VPN comunication with other clients using the Wireguard protocol. If the software fails to establish direct communication it falls back to using relays provided by the company. The IPv4 addresses given to clients are in the Carrier-grade NAT reserved space. This was chosen to avoid interference with existing networks. The configuration also allows routing of traffic to networks behind the client on some clients.