KerioKlone aims to be Windows 95/98/XP/2000 rule based firewall written in C/C++ with similar design and simplicity to but an improvement of Kerio Personal Firewall 2.15, a phased out closed source product. Note: This is not an official Kerio project!
Developers are welcome and needed.
For more details see http://kerio.sourceforge.net/ (homepage) and http://sourceforge.net/projects/kerio/ (Sourceforge.net project page)