The Common Open Research Emulator (CORE) is a tool for emulating networks on one or more machines. You can connect these emulated networks to live networks. CORE consists of a GUI for drawing topologies of lightweight virtual machines, and Python modules for scripting network emulation.
The ODS3 VirtualMachine Challenge are downloadable images that can be run as VMWare or VirtualBox instances. The Idea behind the challenge is to test and exercise web application penetration testing in a controlled environment. These images are great for cyber security students, penetration testers and hobbyist.
Care should be taken if installed on an Internet access host as the application are purposely vulnerable to attack and exploitation.
Libre software to help remember visual and verbal facts.
...These quizzes can be saved for future use, and passed on to friends who may also find them useful.
It is currently supported on Windows and Linux 2.6+, but in theory should work on any machine with a Python interpreter (and wxPython) installed.
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