Vulnerability Scanners

 
Wireshark. Wireshark is a network protocol analyzer that lets you see what’s happening on your network at a microscopic level. With their free software (available for Windows, Linux, OS X, Solaris, FreeBSD, and other platforms), users are able to analyze traffic on their network in real time to detect any potential threats.
 
Rapid7 Nexpose
 
Qualys
 
BeyondTrust Retina
 
Tenable Nessus