Ingate Systems AB Ingate has SIP-capable firewalls and SIParators(TM) (a box that SIP-enables existing firewalls) with support for NAT and VPN.
InnerTek Software InnerTek Software specializes in Linux based firewall suite that includes products for building, configuring, optimizing your Linux firewall solution as well as a redundancy product to ensure uptime.
LiveFire Labs - Online UNIX Training with Hands-on Internet Lab LiveFire Labs proudly offers online UNIX and Linux training with hands-on lab exercises on real servers in the company’s Internet Lab. Courses developed by experienced technology professionals. View sample course before registering.
Merilus Technologies, Inc. Software vendor specializing in network security and managed security systems. Producers of Gateway Guardian VPN and Firewall software.
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.