The SPIRO-Linux EZ-Way Firewall allows you to setup and maintain a firewall easily, and without much strain on resources. It can be set up on a 486 with 8MB RAM, although a much more robust system is recommended for larger networks. This is meant to be a drop in replacement for the expensive and restrictive Firewall products available on the commercial market today.
You can download it from the following link: https://packetstormsecurity.com/files/download/10996/ezwfw.iso
Source: https://packetstormsecurity.com/files/10996/ezwfw.iso.html