NEGOTIATOR by Futures Inc This firewall is designed on top of the Linux OS. VERY EASY to configure and maintain. There is no licensing requirements. Utilizes Network Address Translation. Low cost comparative to other firewalls on the market.
Netasq - The European Firewall box manufacturer NETASQ, firewall box manufacturer, offers easy to install and affordable internet security appliances against hackers, with VPN (IP-Sec encryption), url filtering and regular updates, up to 1200 users per network segment on the internet, extranet or intranet.
Zorp Application Level Firewall The central element of the Zorp Professional is a modular proxy suite. The concept behind the Zorp is that a knowledge to understand a given protocol is definied in a low level proxy implementation.