Are open source security tools really as secure as those available for sale? Yes, say a growing number of enterprises. While some are understandably hesitant to employ solutions that are openly available to hackers and users alike, many organizations are finding that open source tools not only cost less, they are at least as secure as commercial products, if not more so.

(Really a good read for the IT manager or the normal Linux user that wants to increase the secruity of their systems, and they are open source and free. Baldy)

Source: Ten Open Source Security Apps Worth Considering