Making Firefox safe for tests

[Joseph Ollis]

Gavin McCullagh wrote:
> Hi,
>
> On Sun, 16 Dec 2007, Todd O'Bryan wrote:
>
>   
>> Does anyone know how to make Firefox safe for giving online tests? I'd
>> like to prevent students from navigating to different sites, going to
>> different programs, and even from using Copy/Paste while they're
>> taking a test. I realize this is pretty difficult, because you also
>> have to prevent the OS from letting them close the browser or using
>> any of the OS-level keyboard shortcuts, but surely this is a problem
>> someone has solved before?
>>     
>
> It looks like you can do this using firefox extensions such as this one:
>
> http://procon.mozdev.org/index.html
> http://www.glubble.com/
>
> However, my approach to stopping people going to different sites would be
> on a network level, not locking the browser.  Blocking one application
> allows them to still use others.  For example, the command line browser w3m
> would still be there (it's in ubuntu by default) and it wouldn't be locked.
> If you block it at the network level, no browser would be able to connect
> out.
>
> As regards locking them to firefox only, I'd look at setting up a kiosk.
>
> https://help.ubuntu.com/community/EdubuntuFAQ#head-1160489d41f8199cc1c7fcd9850bb5c60863f12b
>
> which automatically launches firefox without gnome.  You can change the
> dhcp so that certain clients boot as kiosks just for the day of the exam.
> Given that they should have no way to launch other applications, I guess
> the firefox extension would work with it too.
>
> Gavin
>
>
>   
I have done this before (at another school) at the network level with a 
transparent <http://freshmeat.net/articles/view/1433/> dansguardian 
machine. When it would come time for the test, I would run a script that 
would alter the iptables & ebtables settings so that dansgaurdian was 
fired up and running. I put the easy sites for cheating (wikipedia, 
search engines, et. al.) on the bannedsitelist. This was a lot of work 
to setup, but hey it worked. I wished that I still had the list and the 
script.

The key to the script was to call the following on ebtables and 
iptables  to activate the filter

ebtables -t broute -A BROUTING -p IPv4 --ip-protocol 6 
--ip-destination-port 80 -j redirect --redirect-target ACCEPT
iptables -t nat -A PREROUTING -i br0 -p tcp --dport 80 -j REDIRECT 
--to-port 8080

And to deactivate

ebtables -t broute -F
iptables -t nat -F


JO
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