I have a location that has a Access point setup for people to bring there computers in and use. They would like to be able to have when someone connects and trys to use the internet it redirects them to a login page where they have to put a code. They would like to be able to change the code daily so the people have to come in and get the code vs sitting in the parking lot using the internet. What is the best way to do this? a computer with 2 nics with the access point connected to 1 and the internet to the other? Is there any good free/open source software to accomplish this?