Autostatus - a network and server monitoring program. It is designed to support large, arbitrarily complex networks of computers, and still provide feedback in a very timely fashion

Big Brother - uses combination of monitoring methods. Unlike SNMP where information is just collected and devices polled, Big Brother is designed in such a way that each local system broadcasts it's own information to a central location. Simultaneously, Big Brother also polls all networked systems from a central location. This creates a highly efficient and redundant method for proactive network monitoring. It also has blinking lights that make it look really cool. Features: Web-based status display, Configurable warning and panic levels, Notification via Pager or email, Support for grouping of machines, Support for modem monitoring, Selectable paging delays, Heterogeneous Network Support.

CTM - CTM is an SNMP interface statistics gatherer which works as a daemon and polls SNMP capable routers in regular intervals and puts the gathered information into a database

The Event Monitor Project - yet another monitoring project; uses TCL.

eEMU - a complete enterprise event management and monitoring system. It is one of the simplest yet most powerful frameworks for writing agents thanks to its time-to-live concept. eEMU has been used for some time in large datacenter environments and is very popular among system administrators due to its simplicity and ability to re-use any existing code/scripts as monitoring agents. eEMU offers a simple messaging "language" to encompass a variety of event management scenarios. It comes with a GUI browser and basic agents (scripts).

Linux Distributed Administration - The Linux Distributed Administration project is a set of programs allowing an administrator to index, monitor, configure and maintain several systems from a single Linux desktop. In the very early stages of development.

MARS - Monitoring Application for Resources and Servers (currently SMTP, POP3, HTTPD, FTP, Free Disk Space.

Mon - a general-purpose resource monitoring system, which can be used to monitor network service availability, server problems, etc.

NetSaint - a program that will monitor hosts and services on your network. It has the ability to email or page you when a problem arises and when a problem is resolved. Several CGI programs are included in order to allow you to view the current service status, problem history, notification history, and log file via the web.

Nettest - a Perl script which tests the integrity of a net connection. If the connection is down, it will either beep the speaker, send email, write in the system logs

Over-CR - a simple system monitoring tool that utilizes a simple language for queries. It is designed as a GPL'd program similar to the popular (and non-GPL) Big Brother Monitoring system.

PIKT - a scripting language that allows distributing monitoring processes, storage, deamons, queues, etc.

Statusd - a server that will wait for connections on a port (4005 by default) and will provide system status and information about various subjects, taken from the /proc file system. The information can be extracted with telnet or with the included xstatus GTK client. Statusd has built in support for allow and deny lists, and various options.

Syswatch - a CGI script to display current information about your UNIX system. It can display drive partitions, drive use, as well as resource hogs, and what current users are doing. It is quite customizable. There are *BSD and Linux versions available.

SMS Client - SMS Client is a UNIX command line based utility which allows you to send SMS messages to mobile phones and pagers. This software has been written and tested on Linux however a number of users have reported success running under both AIX and Solaris.