How to block Internet for guest account?
Solution 1:
First you need to edit the network interfaces file.
Just press Ctrl+Alt+T on your keyboard to open Terminal. When it opens, run the command below.
sudo gedit /etc/network/interfaces
Now you need to add the simple iptables rule to the interfaces file when the internet connection starts up
Simply add this in the interfaces file
pre-up iptables -A OUTPUT -p tcp -m owner --uid-owner username -j DROP
save and exit the file.
Now you need to type in the terminal with the following command
sudo iptables -A OUTPUT -p tcp -m owner --uid-owner username -j DROP
and switch users to the username you blocked and try to access the internet.