Lets assume we need to open port 5900 for RealVNC application:
1. open command line console by typing cmd.exe in the START/RUN
2. lets issue the command at the prompt C:>
3. netsh firewall add portopening TCP 5900 VNC
Once the command is completed, lets issue another command to see what we have done 
netsh firewall show state
This will show/output on your screen stae of your Windows firewall and what ports ar eopen and application allowed
We can easy to use the command in script or batch file to open bunch of ports for our internal use on client machine and also can be used to close the ports if needed.