Iridium Firewall is a very strong ipchains-based firewall with support for 21+ network services (including DHCP, NFS, SMB, HTTP, FTP, Telnet, etc.), masquerading, online gaming, multicasting, TOS flags, and specific port and IP blocking. Protections include twelve different types of IP spoofing, stuffed routing/masquerading, DoS, smurf attacks, control of the full range of ICMP datagrams, and many more. The script is configured completely through the use of a configuration file; no code hacking is required, but it is written so that users that know what they are doing can easily configure the script themselves. Iridium Firewall is heavily commented with instructions and explanations on various topics.
You can download it from the following link: https://packetstormsecurity.com/files/download/24692/if-1.4.9b.tar.gz
Source: https://packetstormsecurity.com/files/24692/if-1.4.9b.tar.gz.html