First, here's a little background for those who might not be familiar with the product. Nessus is a network vulnerability scanner that allows you to probe network systems for potential security holes. Nessus has a long history and is widely regarded as one of the best tools available. For more information on Nessus, read my Nessus 3 Tutorial here on SearchSecurity.com.
The primary advantage Nessus has over the competition is its price tag: the base desktop-scanning product is free for home use and inexpensive for commercial use. If you're looking for a product to run on your desktop to fire off on-demand scans of individual systems or small networks, Nessus is the obvious choice. I use it regularly for this purpose.
On the other hand, if you're looking for an enterprise-class product to run regular, coordinated scans of your organization's network, you're going to want to look at commercial products with more bells and whistles. Tenable Network Security, the producer of Nessus, makes a product called Security Center that coordinates Nessus scans in this fashion.
In my enterprise, we use the software-as-a-service vulnerability-scanning product from Qualys Inc. and are very satisfied with it. If you're considering a product in this price class (we're talking tens to hundreds of thousands of dollars), due diligence demands that you do a side-by-side feature comparison to determine the best product for your environment.
About the author:
Mike Chapple, CISA, CISSP, is an IT security professional with the University of Notre Dame. He previously served as an information security researcher with the National Security Agency and the U.S. Air Force. Mike is a frequent contributor to SearchSecurity.com, a technical editor for Information Security magazine and the author of several information security titles, including the CISSP Prep Guide and Information Security Illuminated.