A system for securing a local computer network, comprising flow analysis means implemented on said local computer network and means for controlling an action to be taken in the event of intrusion detection, comprising sending a message concerning the detected intrusion to an administrator, and for blocking, restricting and/or diverting network traffic, characterized in that it comprises: - a supervision box, - an analysis server communicating via the Internet with a plurality of supervision boxes including said supervision box, and - an application running on a terminal consisting of a cell phone or tablet communicating with the supervision box and the server via the Internet, - said supervision box and said terminal associated with said local network being paired - said supervision box being installed on the local network to be supervised and running a software application for: ▪ extracting digital data from data packets circulating on said local network, ▪ pre-processing and ▪ transmitting to a server time-stamped metadata associating the digital data with an identifier of a relevant supervised device among the supervised devices on the local network, - said server analyzing the metadata transmitted by said supervision box and running a software application for metadata analysis and alert activation - said mobile application executed by said mobile computing equipment of one or more persons authorized to supervise the local network, for: - communicating with said server and with the supervision box in order to receive said alerts - providing means of deactivating certain computer resources installed on said local network, - said deactivation means being constituted by the sending to one of said supervised devices of a message ordering the modification of the IP TABLE, said supervised device comprising a non-volatile memory for recording the state of the IP TABLE when the device is started up. - a supervision box, - an analysis server communicating via the Internet with a plurality of supervision boxes including said supervision box, and - an application running on a terminal consisting of a cell phone or tablet communicating with the supervision box and the server via the Internet, - said supervision box and said terminal associated with said local network being paired - said supervision box being installed on the local network to be supervised and running a software application for: ▪ extracting digital data from data packets circulating on said local network, ▪ pre-processing and ▪ transmitting to a server time-stamped metadata associating the digital data with an identifier of a relevant supervised device among the supervised devices on the local network, ▪ extracting digital data from data packets circulating on said local network, ▪ pre-processing and ▪ transmitting to a server time-stamped metadata associating the digital data with an identifier of a relevant supervised device among the supervised devices on the local network, - said server analyzing the metadata transmitted by said supervision box and running a software application for metadata analysis and alert activation - said mobile application executed by said mobile computing equipment of one or more persons authorized to supervise the local network, for: - communicating with said server and with the supervision box in order to receive said alerts - providing means of deactivating certain computer resources installed on said local network, - said deactivation means being constituted by the sending to one of said supervised devices of a message ordering the modification of the IP TABLE, said supervised device comprising a non-volatile memory for recording the state of the IP TABLE when the device is started up. - communicating with said server and with the supervision box in order to receive said alerts - providing means of deactivating certain computer resources installed on said local network, - said deactivation means being constituted by the sending to one of said supervised devices of a message ordering the modification of the IP TABLE, said supervised device comprising a non-volatile memory for recording the state of the IP TABLE when the device is started up.