The computers are in a private network behind a NAT based router and only the router has a public IP address. You can access the computers inside this private network via the Internet if you configure 'Forwarding' on the router/firewall.
Set up the router to forward connections from a port on the router to a specific IP address and port (Radmin server's default port is 4899) of the target computer in your internal network. You need to assign a port on the router for every computer you need to access. The router will then forward the connection to your computer in the internal network.
Please, read more about port-forwarding here and visit this page to find you router model and set it up.
1. Please download Radmin VPN from here:Radmin VPN.
2. Install Radmin VPN on the local computer.
Create network: Press "Create network" button.

Set Network name and Password.

Press "Create" button.
The new network will appear in Radmin VPN Main window.

3. Download and install Radmin VPN on the remote computer.
4. Launch the software and press "Join network" button.

Enter Network name and Password in the dialog box.

Press "Join" button.
The network created earlier and its nodes will be shown in the Radmin VPN Main window.

The connection between computers has been successfully established.
How to control remote computer via Internet.
1. Download and install Radmin Server on the remote computer.
2. Add user and set user rights in settings for Radmin Server.
3. Download and install Radmin Viewer on the local computer.
4. Connect the local and remote computers using the IP address Radmin VPN.
5. Choose: "Radmin-- > Full control" in the shortcut menu of the remote computer.

6. Enter user name and password which has been set in settings for Radmin Server.

Now you can connect to the Radmin Server by using our free software: Radmin Viewer. Follow the instructions for its installation and configuration below.