ZABBIX is an enterprise-class distributed monitoring solution designed to monitor and track performance and availability of network servers, devices, and other IT resources. It supports distributed and Web-based monitoring, auto-discovery, real-time monitoring, SLA assurance, trending, and more.
OpenNMS is the first enterprise-grade network management platform developed using the open source model. The three main functional areas of OpenNMS are service polling, which monitors services on the network and reports on their "service level"; data collection from the remote systems via SNMP in order to measure the performance of the network; and a system for event management and notifications.
Monit is a utility for managing and monitoring processes, programs, files, directories, and devices on a Unix system. It conducts automatic maintenance and repair and can execute meaningful causal actions in error situations. It can be used to monitor files, directories, and devices for changes, such as timestamps changes, checksum changes, or size changes. It is controlled via an easy to configure control file based on a free-format, token-oriented syntax. It logs to syslog or to its own log file and notifies users about error conditions via customizable alert messages. It can perform various TCP/IP network checks, protocol checks, and can utilize SSL for such checks. It provides an HTTP(S) interface for access.
The sysstat package contains the sar, sadf, iostat, nfsiostat, cifsiostat, mpstat, and pidstat commands for Linux. The sar command collects and reports system activity information. The statistics reported by sar concern I/O transfer rates, paging activity, process-related activites, interrupts, network activity, memory and swap space utilization, CPU utilization, kernel activities, and TTY statistics, among others. The sadf command may be used to display data collected by sar in various formats. The iostat command reports CPU statistics and I/O statistics for tty devices and disks. The pidstat command reports statistics for Linux processes. The mpstat command reports global and per-processor statistics. The nfsiostat command reports I/O statistics for network filesystems. The cifsiostat command reports I/O statistics for CIFS filesystems.
lm_sensors provides essential tools for monitoring the temperatures, voltages, and fans of Linux systems with hardware monitoring devices. It contains a library for sensors access (libsensors), a command-line tool for sensor reporting (sensors), and a daemon (sensord). It also contains scripts for sensor hardware identification and fan speed control.
MoSShE (MOnitoring in Simple SHell Environment) is a simple, lightweight (both in size and system requirements) server monitoring package designed for secure and in-depth monitoring of a handful of typical/critical Internet systems. It supports email alerts and SLA monitoring out of the box, and whatever you can script. The system is programmed in plain (Bourne) SH, and made to be compatible with BASH and Busybox so it can easily be deployed on embedded systems. Monitoring is designed to be distributed over multiple systems, usually running locally. As no parameters are accepted from the outside, checks cannot be tampered or misused from outside. The system is designed to allow decentralized checks and evaluation as well as classical agent-based checks with centralized data accumulation. Agent data is transferred via HTTP, so available Web servers can be co-used for agent data transfer. Each agent creates simple (static) HTML pages with full and condensed status reports on each system, allowing simple local checks.
Snort is a network intrusion detection and prevention system. It is the most widely deployed technology of its kind in the world. It performs detection using a variety of methods including rules-based detection, anomaly detection, and heuristic analysis of network traffic. Its rules language is open source and available to the public as well.