Open Source AWK Network Monitoring Software

Master/node to gather and graph "everything" on your systems using Tobi Oetiker's rrdtool. It can optionally warn your surveillance software. This software package was originally called LRRD. The project. Please see http://munin-monitoring.org/

LogCop is a set of turn-key bash/firewall/awk scripts for enhancing an IDS. It monitors system logs and blocks IP addresses based on such criteria as illegal user names from repeated attacks. In production under Linux, FreeBSD, OS X, Solaris.

Always more than one-way script based nms plugins. Nagios add-on project with plugins and tools.