The heart of the PNS-based firewall solution is the firewalling software itself, which is a set of proxy modules acting as application layer gateways. PNS is an application proxy firewall. For details on the architecture of PNS itself, see Section 2.2, The concepts and architecture of PNS firewalls.

PNS must be installed on an Ubuntu-based operating system (Ubuntu 22.04 LTS) which installs automatically when booting from the PNS installation media.