Firewall Builder consists of object-oriented GUI and set of policy compilers
for various firewall platforms. In Firewall Builder, firewall policy is a set
of rules, each rule consists of abstract objects which represent real network
objects and services (hosts, routers, firewalls, networks, protocols).
Firewall Builder helps user maintain database of objects and allows policy
editing using simple drag-and-drop operations.

Preferences and objects databases are stored in XML format. 
GUI and policy compilers are completely independent. Support for a new firewall
platform can be added to GUI without any changes done to the program, although
new policy compiler must be written. This provides for consistent abstract
model and the same GUI for different firewall platforms. Currently three most
popular free firewalls are supported: ipchains, iptables and ipfilter.
Because of this, Firewall Builder can be used to manage firewalls built on
variety of platforms including, but not limited to, Linux running ipchains or
iptables and FreeBSD or Solaris running ipfilter. 

WWW: http://www.fwbuilder.org/