A new approach for the information security (IS) improvement of the educational institution's network has been proposed. The proposed approach is structured and systematic. It allows one to assess the security of the network of an educational institution (for example, a university) as a whole, as well as its subsystems and components that provide IS of an educational institution. Statistical, expert, heuristic and other indicators have been used to assess the degree of security. The proposed model allows one to describe the procedure for securing the IS network of the university. A balanced system of IS indicators has been proposed, which will allow the effectiveness evaluation of the university's network protection. Also as part of the research, a model of a secure network of an educational institution has been built, where network devices were emulated in a virtual machine (VM) with the EVE-NG application installed. Other network resources have been reproduced with the server virtualization system Proxmox VE. The IPS Suricata threat detection system, the Splunk platform, and the Pi-Hole DNS filter have been deployed on PVE-managed hosts.