Web-based auth. for router internet access
First I'll try to describe what I'm attempting. I'm hoping to set up a wireless router to offer authentication through a web interface. In other words, it would not be encrypted (i.e. no WEP/WPA), but newly connected users would have their browsers redirected to a webpage requiring them to download and execute an authentication client or daemon. As an example, I've seen this done before in commercial environments like hotels or university residences, to ensure proper end-user antivirus protection.
Unfortunately, my router doesn't have any such feature, and isn't re-programmable (afaik), so this would need to be implemented separately from the router itself. I'm thinking it might be done by setting up a Linux box between the internet connection and the router. For what it's worth, this is the picture I've got in my head of how it might work, although if a better solution exists, I'd jump on board quicker 'n lightning. Feel free to call me an idiot =)
1. Linux box is running 3 daemons: web server, DNS server, and some custom authentication server.
2. When clients connect to the wireless router, DHCP serves up the Linux box's DNS server instead of the ISP's.
3. On host lookups, the Linux DNS checks with the auth server to see if the client's authenticated; if not, the lookup returns the IP of the web server, which allows the client to download an auth client.
4. If the client is running the auth client, the DNS server passes requests directly to the ISP's DNS servers.
The main problem I have, is simply that I have no idea where to start looking for software of this sort, or even if it exists in open source. If anyone can just point me in the right direction of what to look for, I'll be eternally in your debt (or at least, until I can repay the favor =P ). Thanks!