Monitor logfiles, scan for specific entries in the log file, and take the action you have determined. Use with tcp_wrappers for excellent monitoring system.
You can download it from the following link: https://packetstormsecurity.com/files/download/12841/swatch-2.2.tar.Z
Source: https://packetstormsecurity.com/files/12841/swatch-2.2.tar.Z.html