Pen Oasis is a free network testing tool that provides you with the ability to scan your network infrastructure for susceptibility to DOS or DDoS attacks.

Pen Oasis achieves this by hitting your network with an attack, after completion, it then informs you whether the attack was a success. If your network is secure then there is no message and the program simply terminates.

In order to start the testing process you need to enter your valid IP address as well as a TCP port number - once you press the 'attack' button there is no way to abort the test.