[1] Nessus [<http://www.gfi.com/products-and-solutions/network-security-solutions/gfi-languard>]
[2] OpenVAS [<https://www.rapid7.com/products/nexpose/>]
[3] Nexpose [<https://www.rapid7.com/products/nexpose/>]
[4] GFI LAN Guard [<http://www.gfi.com/products-and-solutions/network-security-solutions/gfi-languard>]