Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for a host state machine. In one aspect, the method includes defining a state machine in a memory of a data processing apparatus, the state machine comprising a plurality of states, and wherein network access for a host device is controlled in each state according to one or more network access zones associated with the state, each network access zone defining network access capabilities for the host device; monitoring, by the data processing apparatus, host devices attempting to access the network and host devices that have access to the network; and transitioning, for each host device, a state of the host based on the monitoring and a current state of the host.