Samsung SVR-1650 connection established but no video is displayed on Network Viewer even the Network Manager reports that the connection is successfully established. This is the case when the DVR is behind private server/router with active firewall/NAT. Of course knowing that the default port is 4000, shown everywhere (manual, SVR-1650 settings, etc) and recommended by manufacturer, obviously everyone will open and forward this port on server/router, that’s why the connection is established with no issues but the trick is that the video signal is sended via next ascending ports, each camera channel has its own port. So if you start with 4000 as default, camera 1 has 4001, camera 2 has 4002 and so on. Obvious solution is to open and forward each and every port, to allow video signal to pass through. Bellow are related images to make clear how it works.