A technique for controlling access to a network provides an electronic system that includes multiple antennas located in a physical space. The antennas receive wireless signals at their respective locations from devices within range of the antennas, and the electronic system processes the wireless signals as received by the antennas to measure locations of the devices relative to the antennas. The electronic system then allows or denies access to the network depending on whether the devices' measured locations are inside or outside a predefined physical region relative to the antennas. In this manner, only devices confirmed to be physically present within the predefined region are allowed to access the network. Devices outside the predefined region are physically blocked, such that no wireless communication with the network is possible.