Access - Remote control

To do NAS far end control, it is never easy if NAS is locating behind the router. Although the user manual describe the setting so easy, it doesn't work on my case. According to manual, we need to go to [Network] -> [Remote Access] and enable UPnP port forwarding. If we need a name address, we have to enable DDNS. However, I still need to do something on my router to enable remote access.

I need to set port forwarding to the internal address of NAS as:

port 21 for ftp / port 80 for http / port 9090 for file viewer / port 9091 for torrent

Remember that do not test remote access inside the home network where NAS located.