Open source versus commercial firewalls: functional comparison
Samuel T. Patton, D. Doss, William J. Yurcik · 2002
This paper compares firewall alternatives with virtual private network support appropriate for corporate applications. Two specific firewall solutions are compared highlighting corresponding security risks: (1) a firewall constructed using only open source software available for the Linux operating system and (2) a commercial firewall solution from Cisco using the Cisco IOS firewall feature set.