title: how to check open ports in my firewall
body: <p>I have an internet connection from school, where there are restriction about what ports webapp can use. Is it possible, to use my computer to check what ports are allowed to use and can be used? I'm having problem with websockets in couple of locations, so I would like to use client computer to do that. Is there any snippet of code that I can run in chrome console or any command line command?</p>