Cisco® Network Admission Control (NAC) Appliance, formerly known as Cisco Clean Access, provides a powerful host security policy inspection, enforcement, and remediation solution that is designed to meet these new challenges. Cisco NAC Appliance allows you to enforce host security policies on all hosts (managed and unmanaged) as they enter the interior of the network, regardless of their access method, ownership, device type, application set, or operating system. Cisco NAC Appliance provides proactive protection at the network entry point.