Let me introduce you to PortQuiz. It's an outgoing port tester with which you can find out if ports are opened for connection or not. Very helpful if you find the network you are connected to being restrictive so you'll always know which ports you can use to connect to AirVPN without trying to establish a connection. You can use it on many ways. The easiest is to just connect with your browser to a port you want to check, for AirVPN's ports for example the URLs will be http://portquiz.net:53 (Firefox may block this one. Use IE or a command line app like telnet) http://portquiz.net:80 http://portquiz.net:443 http://portquiz.net:2018 If you can reach the website the port is open. Fast and easy. The site also supports a variety of services started via command line (FTP, SSH,..).