DATA TRANSMISSION CONTROL ON NETWORK

Enables control of data transmission within a network. For this, for example, a network relay apparatus makes a determination as to permission to transmit data, based on a condition relating to at least one of the transmission origin of the data and transmission destination of the data. An administration unit contains administration information indicating permission to use shared devices by users of clients. The connection relay apparatus for a target client acquires user identifying information from the target client. The administration unit acquires the user identifying information from the connection relay apparatus for a target client, and referring to the administration information, detects a target shared device that is one of the shared device permission to use of which has been granted to a user of the target client. The administration unit notifies the connection relay apparatus for the target shared device of permission for transfer of data between the target client and the target shared device, together with information identifying the target client. Upon receiving the notification, the connection relay apparatus for the target shared device sets the condition so as to change the data transmission permission between the target client and the target shared device from not authorized to authorized.