Seawall is an ipchains firewall that supports IP masquerading and can be used on a standalone system, on a dedicated firewall system or on a multi-use gateway/server. It supports VPN via IPIP tunnels and PPTP, has an easy to edit configuration file, and can be extended without modifying the base product. It also includes realtime monitoring with an audible alarm that sounds when suspect packets are detected.
You can download it from the following link: https://packetstormsecurity.com/files/download/16883/seawall-2.5.tar.gz
Source: https://packetstormsecurity.com/files/16883/seawall-2.5.tar.gz.html