how to remote to windows server but when open ip open router

To be able to remote into the Windows server, you need to do the following:

1. Sign up for a hostname at https://www.dynu.com/en-US/ControlPanel/AddDDNS and run the IP update client software on your Windows machine to keep the hostname mapped to the most current IP address.

2. Open port 3389 in the router following the instructions at https://www.dynu.com/Resources/Tutorials/DynamicDNS/RouterandDevices/RouterPortForward

The router usually has settings to allow/disallow remote connections. You should check the router settings and enable remote connections to the router then you should be able to connect to the router using its IP address. To access your router inside the network, you should use the router's internal IP address(usually in the form of 192.168.0.1)