where will i get basic firewall source code in C ???

hello friends...
i want to know from where can i get a sample source code of a firewall in C languge. i want to code my own firewall , just to learn how a firewall works... and how to program it.. but i am not able to locate any source anywhere... i have also searched google.com but it takes me to some sites which shows "what is firewall ?"

but i need some basic source code .... in C language...

can anybody help me ....

intruder

I've not taken the time to strip down the packages yet to ensure that they are exactly what you are looking for, but some time ago I came across this : http://www.ifi.unizh.ch/ikm/SINUS/fi.../download.html

I think this is along the lines of what you are looking for.. But never having completely checked, I can't be positive. If I do recall correctly, the search I had used to locate this kind of thing was "open source firewall"
Obviously most results will pertain to *nix, but they should give you the ability for some groundwork.

Hope this helps.
Regards.

thank u so much ... chefer i have downloaded the source ... and i am going through it .. let me see if i understand anything... ?

thanks once again...

intruder