What is NAC?

NAC is a method by which access to network resources is granted based upon authentication of the user and device as well as verification of the device's compliance to policy.

NAC aims to control access to a network. The term is also sometimes used for Network Admission Control, which is focused on authenticating users and performing a posture check on the connecting device. The broader definition of NAC, as access control, includes pre-admission endpoint security policy checks and post-admission controls over where users can go on a network and what they can do.

Policy decision may be separate from policy enforcement - this architecture is often called an out-of-band deployment. When policy decision and policy enforcement occur in the same device, this is called an inline deployment.

What are the objectives of NAC?