Shield is an aggressive, modular firewall script for iptables which features easy configuration through a BSD-style configuration file, optional NAT support, TCP-wrapper-like functionality for service access, port forwarding, routable protection, DMZ support, and more.
You can download it from the following link: https://packetstormsecurity.com/files/download/24645/gShield-2.3.tgz
Source: https://packetstormsecurity.com/files/24645/gShield-2.3.tgz.html