Firewall Builder is a GUI firewall configuration and management tool that supports iptables (netfilter), ipfilter, pf, ipfw, Cisco PIX (FWSM, ASA) and Cisco routers extended access lists. Both network administrators and hobbyists managing firewalls with policies more complex that is allowed by simple web based UI can simplify management tasks with the application. The program runs on Linux, FreeBSD, OpenBSD, Windows and Mac OS X and can manage both local and remote firewalls.
iptables is a user space application program that allows a system administrator to configure the tables provided by the Linux kernel firewall (implemented as different Netfilter modules) and the chains and rules it stores. Different kernel modules and programs are currently used for different protocols; iptables applies to IPv4, ip6tables to IPv6, arptables to ARP, and ebtables as a special for Ethernet frames.
eBox Platform is an open source unified network server (or an Unified Network Platform) for SMEs. eBox Platform can act as a Gateway, a Network Infrastructure Manager, a Unified Threat Manager, an Office Server, a Unified Communications Server or a combination of them. Besides, eBox Platform includes a development framework to ease the development of new Unix based services.
Shorewall is an open source firewall tool for Linux that builds upon the Netfilter (iptables/ipchains) system built into the Linux kernel, making it easier to manage more complex configuration schemes.
Monowall is an embedded firewall distribution of FreeBSD, one of the BSD operating system descendants. It provides a small image which can be put on Compact Flash cards as well as on CDROMs and hard disks. It runs on a number of embedded platforms and generic PCs. The PC version can be run with just a Live CD and a floppy disk to store configuration data, or on a single Compact Flash card (with an IDE adapter). This eliminates the need for a hard drive, which reduces noise and heat levels.