In Greek mythology, Nessus was a centaur who was killed by Hercules for attempting to kidnap his beautiful wife. As Nessus was dying, he convinced Hercules' wife to take his poisoned robe to prevent Hercules from leaving it. It wasn't long before Hercules' wife gave Hercules the robe of Nessus, poisoning him so that he would die in torment. Today, Nessus is a popular vulnerability scanner that detects security vulnerabilities. It was introduced as an open source project more than 13 years ago and later evolved into a commercial product now maintained by Tenable Network Security. It is known as one of the best and most used vulnerability scanners in the world, thanks to its rich feature set and profound advantages. If UMUC is looking for a robust and affordable vulnerability scanning solution, Nessus 5.2.1 is definitely the way to go. Since its release in 1998, the Nessus vulnerability scanner has offered a free version for home users; however, the professional version provides vendor support and access to the latest updates. The professional version also offers compliance checks (PCI, NIST or CIS) and virtualization support. The annual professional license fee is around $1,500, which is very affordable compared to other commercial vulnerability scanners. If UMUC plans to conduct vulnerability assessments on a regular basis, opting for the professional version makes sense, because the free version lags the professional version by seven days and does not include advanced features that can be used to search for policy and data breaches sensitive, such as social security numbers.Nessus is an efficient and comprehensive vulnerability scanner that provides fewer false positives than many other tools currently available in... middle of paper ......oss linking between compliant security tools . Additionally, Nessus is supported on Windows, Linux/UNIX, and Mac OS X. This makes it a great all-round tool to use in a mixed client environment. You can define user rights to block the types of scans they can perform. If users are more familiar and comfortable with Windows, they can use the Windows client to run scans. There are no major differences between each specific version, but network scanning performance is much better on Linux/UNIX based systems. With such powerful and comprehensive tools available like Nessus, it is difficult to justify spending thousands or tens of thousands of dollars to implement a vulnerability scanning product. If UMUC is looking for a robust and affordable vulnerability scanning solution, Nessus 5.2.1 deserves to be on the short list of products to test and consider.