A simple way to block access to the internet per app
OpenSnitch is a GNU/Linux port of the Little Snitch firewall
Firewall able to analyze visitor behavior & provide adapted response
Manage port forwardings via UPnP
One of the most advanced DNS Proxy and DNS Firewall in one product.
OWASP ModSecurity Core Rule Set (CRS) Project
Powerfull Web Application Firewall for PHP
Webinterface to (un)ban IPs in Fail2Ban
Extract and Convert Juniper Firewall Policies to CSV