About:

A captive portal is a bit of software trickery that captures network requests going over a device and redirects those requests to a special web-page where you ask for something from your users. Places like Mcdonalds, Starbucks and Panera use captive portals. Most often a captive portal just requires you to agree to some terms and conditions before it lets you continue browsing the internet.

I created this captive portal to use with a Raspberry PI acting as an access point. I used the portal to test portal-discovery on several mobile-devices and applications. You can see my other repository "raspberryap" for information on how to configure a raspberry pi as an access point.

This captive portal still needs some work. It doesn't properly handle HTTPS redirection, and it also proxies all allowed traffic, which it should just change the routing rules to allow or disallow a list of clients based on hardware address. I'll fix that in the future.

Notice:

The captive portal issues iptables commands that add rules. These commands are reversed/removed when the captive portal is stopped using the sudo captiveportal stop command.

The captive portal limits the redirection to a single interface, by default wlan0.

Installation:

1.) Download and unzip, or clone this repository
2.) Ensure you're in the directory containing the setup.py file
3.) In a command prompt type: sudo python setup.py install

To manually install the captive portal (if setup.py doesn't work):

1.) Copy "captiveportal" to /usr/bin/captiveportal
2.) chmod 755 /usr/bin/captiveportal
3.) sudo apt-get install python-twisted python-twisted-web

Using the captive portal:

First you may have strange behavior if the tablet is connected to a server not listening on port 80. The portal works BEST when all requests are heading through port 80.

run sudo captiveportal start to start the portal.

run sudo captiveportal stop to stop the portal.

run sudo captiveportal start --help for configuration options.

to reset which addresses are allowed: sudo captiveportal reset

Note:

Sometimes there is a delay in the portal working because of already-active http connections that will wait to be re-used. The captive portal attempts to issue a command to reset these connections but there may be times when you have to simply wait until your device closes all open http connections before the portal will start working.