Typically, when you connect to a Windows-based terminal server, you connect to port 3389. However, if someone has changed the listening port on the terminal server (by changing the value of the HKEY_LOCAL_MACHINESYSTEMCurrentControlSetControlTerminal ServerWinStationsRDP-TcpPortNumber subkey), you need to tell the client to connect to the new port. To do so, add a colon and the new port number after the server name, as this example shows:
TServer:3389