Captive portals allow you to leverage a common browser as a secure authentication device. They also have the potential to allow you to do everything securely via SSL and IPSec and setup per user quality of service rules, and still maintain an open network. If you are curious about why you might want to install a captive portal please see WhyCaptivePortal. You can also see the beginning of our software requirements process at CaptivePortalDefinition.

Captive portals are becoming a popular way for SMS/BSN vendors to provide user authentication and IP flow management (basically traffic shaping and bandwidth control) without a required client application. They work by forcing un-authenticated users to a web page, once you have "captured them" this way by allowing the web page to interact with the router/firewall you can completely control their access.

As far as I am aware no OpenSource software has ever been developed to do this and plan to write this software as part of ThePlan.



Usage Flow:

Comments and Thoughts:

I think that this is all relatively straight forward to implement. It'll basically just be a matter of setting up the user database, and some web scripting to interact with the server to change system settings. The reason for a central user database (instead of sticking with the autonomous system model we use elsewhere) is that it makes authenticated roaming possible and also moves the user database (really the only important data that the portals will store) to a more reliable distributed model. We'll see if it's really as easy as all that ... :-)

Why bother with this? Because I want to avoid the tragedy of the commons. If we just open up our networks sooner or later people will start to abuse it because they didn't work to set it up and they don't know the people that did. I want this to be an open network by choice rather then because we don't have the ability to control it. The time will come when we're going to be forced to control it or the network will die from abuse.

Why do something like this instead of PPPOE, IPSec or Authenticated DHCP?

Information from Other Projects:

-- AdamShand

Additional note on potential hardware: FreeGeek has lots of old 486 boxes I bet they would be happy to give by the dozens to act as routers or hubs. (Would need to be router-on-a-floppy or other tiny linux, I suppose, as most large, working hard drives they have, they use.) -JonGracie


Btw, I would assume that NoCat is now a valid system for such a captive portal, is it ?... Maybe a question of the time this was written ? -OlivierBerger