An iptables IPv4 firewall and traffic shaping program
OWASP ModSecurity Core Rule Set (CRS) Project
Programmable completion code (bash) for ip[6]tables (netfilter.org)
download and convert ip block list
Programmable completion code (bash) for ipset (netfilter.org)
Easy to use firewall for linux beginners.
Drop specified IP n seconds remotely, auto-undrop it when timeout.