I have a (maybe) odd setup where I need a solution - I have a lab that is setup inside a private company network. for various reasons, we are using a Linux NAT firewall to enclose a section of the lab so that we can have a larger network without using company provided IP addresses, and contain the DHCP and DNS services needed for some applications.

We set the RED interface of the firewall on a company provided IP address, set up a Windows VM on the same network, and configured OpenVPN on the Windows VM to allow a route into the private network.
This works, but is generally annoying as we have obvious stability issues with Windows 2003/2008 server in this capacity.

Is it possible to set up VNC on a linux desktop so that the clients that have only MS RDP clients can access it without having to install a VNC client?