http://www.eeye.com/Products/Retina/Community#

Retina Network Community, a free vulnerability scanner for up to 128 IPs gives you powerful vulnerability assessment across your entire environment.

With Retina Network Community you can:

• Reduce risk and improve security with complete vulnerability scanning across operating systems, applications, devices, and virtual environments.
• Comprehensive vulnerability database that includes zero-days and is continually updated by eEye’s renowned research team.
• Improve risk management and prioritization with broad exploit identification from Core Impact, Metasploit, and Exploit-db.com.