I wrote something tangentially related, but for single user.<p>"gofwd" is a cross-platform TCP port forwarder with Duo 2FA and Geographic IP integration. Its use case is to help protect services when using a VPN is not possible. Before a connection is forwarded, the remote IP address is geographically checked against city, region (state), and/or country. Distance (in miles) can also be used. If this condition is satisfied, a Duo 2FA request can then be sent to a mobile device. The connection is only forwarded after Duo has verified the user.<p><a href="https://github.com/jftuga/gofwd">https://github.com/jftuga/gofwd</a>