As with all ethical hacking, your network security tests require the right tools — you need port scanners, protocol analyzers, and vulnerability assessment tools. Great commercial, shareware, and freeware tools are available. Just keep in mind that you need more than one tool because no tool does everything you need.
If you’re looking for easy-to-use security tools with all-in-one packaging, you get what you pay for most of the time — especially for the Windows platform. Tons of security professionals swear by many free security tools, especially those that run on Linux and other UNIX-based operating systems.
Many of these tools offer a lot of value — if you have the time, patience, and willingness to learn their ins and outs. It’d behoove you to compare the results of the free tools with that of their commercial counterparts.
Scanners and analyzers
These scanners provide practically all the port scanning and network testing you need: