Journal of Information Security Research Liliia P. Galata, Bogdan Y. Korniyenko, Alexander K. Yudin 15 3 2024 https://doi.org/10.6025/jisr/2024/15/3/89-102 https://www.dline.info/jisr/fulltext/v15n3/jisrv15n3_1.pdf This work develops and implements a simulation boundary designed to safeguard essential data assets using the application software GNS3. At the core of computer network security lies the Cisco ASA 5520 firewall, which segments the organization’s network into a demilitarized zone, encompassing an internal and external network. Within this demilitarized zone, web and FTP servers are set up. A network scan was conducted with the Zenmap utility to evaluate the effectiveness of the simulation boundary for critical data protection. Additionally, a stress test of the network was carried out using the hping3 utility. The measures taken to counter these simulated attacks were identified and documented.