Technology

The above is just modern network security. The model is called zero trust.

Zero trust assumes there is no implicit trust granted to assets or user accounts based solely on their physical or network location (i.e., local area networks versus the internet) or based on asset ownership (enterprise or personally owned). Authentication and authorization (both subject and device) are discrete functions performed before a session to an enterprise resource is established. Zero trust is a response to enterprise network trends that include remote users, bring your own device (BYOD), and cloud- based assets that are not located within an enterprise-owned network boundary. Zero trust focus on protecting resources (assets, services, workflows, network accounts, etc.), not network segments, as the network location is no longer seen as the prime component to the security posture of the resource.

Google pionerred it in the 2000s I believe, but its very normal now. A commom deployment will have an always on vpn agent on each device, which will then use mesh vpn tech like wireguard to do peer to peer connections between the client and server. There is no need for a central vpn controller. At most their is a dns-ish directory service that runs to let each agent queiry to get public keys for the other agents. Access is gated with RBAC and ACLs.

Tailscale is well known name that provodes this model. Netbird is a FOSS example.