Internal network, VPN and RDP connection. How?

Question

VPN

There is a remote server with a white IP XX.XX.XX.XX
On it Windows Server 2012 (DHCP, DNS, Router, HyperV, ...) IP 172.168.0.1
in HyperV is configured by a workstation
The workstation has Win7 with IP 172.168. 0.100
NAT is configured on the server and port forwarding 3389 (RDP) to the workstation
Sometimes it is necessary to connect via VPN to another network. And at this time access on RDP falls off. As I understand it, the connection request reaches the workstation, but it goes back along the VPN route or something else, but the connection is not established.
And here's the question: How to set up a connection from the Internet to a workstation via RDP with VPN enabled?
As I think it is necessary to register static routes, but I can not figure out which and where.

Answer 1

Most likely the vpn server gives you a default gateway, you need to register on the vpn machine a route for the white address XX.XX.XX.XX through the internal address (from the network 172.168.0.0) of the same server. For beauty, this route can be given to the vpn server.
For Windows, the route looks something like this route -p add external_address_to which_you_are_connecting_by_RDP_mask 255.255.255.255 internal_address_of_server_which_has_driven_traffic (from network 172.168.0.0)

Answer 2

Use the route command