How to know who using what port (linux/window)

That one is easy, on linux use netstat :

netstat -tlnp | grep 9998

replace 9998 with the port you want to check.

More on net stats here : http://www.thegeekstuff.com/2010/03/netstat-command-examples/

On windows :

netstat -an |find /i “9998”

replace 9998 with the port you want to check.

 More info on netstat on Microsoft site or here on Quickly Find Local Open Ports.