When I open the link: “http://www.linux-firewall.org/”, it gives the following message: "Web page not available
The web page at http://www.linux-firewall.org/ could not be loaded because:
net::ERR_CONNECTION_TIMED_OUT", can you solve it please?
You can use any firewall for Linux. This was just one example given which is now changed. You can google ‘best linux firewalls’ and start with any of them to understand.