Under ideal conditions, which frequency band will have the farthest usable range?

A Mist access point is booting up, and will soon receive a channel assignment from the Mist Cloud. The channel assigned by the cloud is a DFS channel.
In this scenario, what must the AP do before broadcasting an SSID on the channel?

A customer wants to physically wire their interior automated sliding doors to Mist APs to directly control location access to certain office areas.
In this scenario, which Mist AP capability allows them to accomplish this task?

A user is experiencing DNS problems.
In this scenario, where in the GUI would you be able to see the problems?

You have discovered an access point that is not connected to the corporate network but it broadcasts the corporation's SSID.
In this scenario, what is this type of access point called?