The single most popular piece of the Cisco NAC solution has been the Cisco NAC Appliance. As evident from the name itself, Cisco NAC Appliance is an appliance-based solution that offers fast deployment, policy management, and enforcement of security policies.
With the Cisco NAC Appliance, you can opt for an in-band or out-of-band solution. The in-band solution is for smaller deployments. As your network grows into a more campus environment, you may not be able to keep in the in-band design. In that case, you can move to the out-of-band deployment scenario.
Here are some advantages of the Cisco NAC Appliance:
Identity: At the point of authentication, the Cisco NAC Appliance recognizes users, as well as their devices and their responsibility in the network.
Compliance: Cisco NAC Appliance also takes into account whether machines are compliant with security policies or not. This includes enforcing operating system updates, antivirus definitions, firewall settings, and antispyware software definitions.
Quarantine: If the machines attempting to gain access don’t meet the policies of the network, the Cisco NAC Appliance can quarantine these machines and bring them into compliance (by applying patches or changing settings), before releasing them onto the network.