Is it possible to use an Android Firewall for a wifi connexion with proxy ?

Hi,

I Need some help on using Greyshirts "Firewall no root" on Android 12 :

https://play.google.com/store/apps/details?id=app.greyshirts.firewall

I'm a teacher and i wished to use this firewall on pupils tablets to whitelist only the websites they are allowed to browse.

My project is working mostly within a local server in my classroom where pupils have access to the data needed for their work (using for example KIWIX project).

So i only need to let them access to a few websites (NASA and some other science websites) and block all others, to avoid pupils going to youtube or games websites, because it was a major source of lack of concentration last years.

In my school, all internet traffic is redirect to an internal proxy server (via 172.16.0.1) that has its own firewall filters rules.

This firewall is managed by an academic outside service and have general rules that are not enough restrictive for my project. I have no way to ask them to add specific rules only for my classroom, as other teachers have different usages of internet.

If I don't use this academic proxy, all internet connexion is blocked, so i have no choice that to use a wifi connexion on the tablet with this proxy.

When i have tried "Firewall no root" at my home (without proxy) it works very well, so i have thought i would you use it at school the same way to be sure my pupils can browse only the needed websites.

But when i try it at school, i had to add the proxy to the wifi connexion, and then discovered that the browser Chrome redirects all urls to 172.16.0.1 because of the proxy settings, so "Firewall no root" sees only the proxy url 172.16.0.1 instead of the real adress entered in the browser.

So i have to add a rule to allow "172.16.0.1" but then all real urls are again allowed and nothing is filtered anymore.

I didn't see any parameter in "Firewall no root" to tell him that Chrome goes through a proxy, so that it has to filter not the proxy url, but the website url (maybe contained in the header of the request or something like that).

Is there an Android parameter to resolve this problem or do you know another way to acomplish this with a free app (I have no budget for that).

Thank's for any help.

All no root firewalls run your data through an outside site to perform the filtering. You may want to consider there privacy policy if you are going to have students use that service.