I'm using the Cisco NAC framework in order to authenticate both users and machines before granting network access. i'm using windows AD to authenticate users and machines.
Under "External User Databases" -> Windows Authentication Configuration, you can configure some machine authentication settings.
I have to enable "Enable Machine Access Restriction" in combination with the group map "no access". Otherwise, even though machine authentication has failed, an authorized user can still login with an unauthorized machine (it will only appear in the failed attempts log but it will not be restricted).
This works, but the problem is the "aging time". The ACS caches the machines for a certain amount of time (12 hours by default). Now if a user logs off and he waits 12 hours to logg back on, authentication will fail (because machine authentication is already performed just after being logged off).
Is it possible to force machine authentication (together with the user authentication) at Windows log on?