Annotation: The article considers a network monitoring system for the security of a data transmission network operating under computer influences. One of the most urgent tasks in these conditions is the development of mechanisms for evaluating the effectiveness of network monitoring of data transmission network security from computer influences. A mathematical model and methodology are proposed, where the fundamental difference from the existing ones is a new approach to monitoring the security status of data transmission network elements from computer influences.

Keywords: data transmission network, network security monitoring, computer impacts, efficiency assessment