An analysis of the requirements of guiding documents for ensuring the security of critical information infrastructure facilities has been carried out. A classification of information security tools of the firewall class with a description of each, their implementation scenario and a generalized network diagram, taking into account the application of these solutions in the field of information security, are presented. A comparative analysis of existing firewalling solutions is made, followed by conclusions about using some of them to protect critical information infrastructure facilities. A solution is offered to develop the functionality of a new generation firewall