This is a very simple cpative portal that uses IPTABLES and python's BaseHTTPServer. When it is executed it blocks all traffic except DNS and redirects all HTTP traffic to a login page. When a user enters the correct credentials a new IPTABLES entry is added and all the traffic originating from the IP address of that user is allowed.

It is highly recommended to flush IPTABLES before using this scipt. You can do that using the following commands

$ sudo iptables -F
$ sudo iptables -t nat -F

Modify the PORT, IFACE, and IP_ADDRESS variables according to your needs. Moreover, if you plan to use this code for something more than proof of concept make user you modify the dummy security check at line 69 of the script.

Run the script with su priviledges. The username and the password used in the provided script are nikos and fotiou respectively.