A network probe terminal for surveillance of a network communication line and simulating browser activity of a given terminal is disclosed. The probe terminal monitors TCP/IP data packets routed through the communication line and filters relevant requests and responses relating to a given IP address. These requests and responses are analyzed and sorted according to their type and content. Based on the analysis, the probe terminal identifies all relevant data transactions relating to the navigation process of a given terminal. The probe terminal activates a virtual browser simulating the processing of identified data transactions to create navigation presentations similar to the navigation presentations as seen by the user of a given terminal.