Next Generation Open Source Firewall
Web application firewall in C language uses libevent
A simple, portable port scanner
One of the most advanced DNS Proxy and DNS Firewall in one product.
A powerful network security tool, easy, safe and totally free.
PeerGuardian - a privacy oriented firewall application
Network Firewall Linux Kernel Module with Conflict Resolution Engine
IoT Device, Gateway, Server platform
Personal firewall for linux desktop and android phone