Start a captive portal

Hi,

I would like to develop captive portal software, as http://www.antamedia.com/hotspot/

Will be installed on a machine with windows and two NICs. I share the internet from one network card to another. The NIC 1 is connected to the internet and 2 network adapter is connected to a wi-fi router.

All laptops, phones and tablets will connect to wi-fi router.

My software needs only to present a login page to authenticate users and free up your internet access after authenticated.

My question is how to start this project with WinpkFilter?

I got it run the wwwcensor project, i managed to block access to certain words, in the environment that I created, all requests from the router comes with the same IP and with that I can not block access to a specific IP.
Can someone help me?

Thank you very much.

Regards,

Pedro