open source network management

Nagios

Nagios® is a host and service monitor designed to inform you of network problems before your clients, end-users or managers do. It has been designed to run under the Linux operating system, but works fine under most *NIX variants as well. The monitoring daemon runs intermittent checks on hosts and services you specify using external "plugins" which return status information to Nagios. When problems are encountered, the daemon can send notifications out to administrative contacts in a variety of different ways (email, instant message, SMS, etc.). Current status information, historical logs, and reports can all be accessed via a web browser.

Nagios has a lot of features, making it a very powerful monitoring tool. Some of the major features are listed below:

Monitoring of network services (SMTP, POP3, HTTP, NNTP, PING, etc.)
Monitoring of host resources (processor load, disk and memory usage, running processes, log files, etc.)
Monitoring of environmental factors such as temperature
Simple plugin design that allows users to easily develop their own host and service checks
Ability to define network host hierarchy, allowing detection of and distinction between hosts that are down and those that are unreachable
Contact notifications when service or host problems occur and get resolved (via email, pager, or other user-defined method)
Optional escalation of host and service notifications to different contact groups
Ability to define event handlers to be run during service or host events for proactive problem resolution
Support for implementing redundant and distributed monitoring servers
External command interface that allows on-the-fly modifications to be made to the monitoring and notification behavior through the use of event handlers, the web interface, and third-party applications
Retention of host and service status across program restarts
Scheduled downtime for supressing host and service notifications during periods of planned outages
Ability to acknowlege problems via the web interface
Web interface for viewing current network status, notification and problem history, log file, etc.
Simple authorization scheme that allows you restrict what users can see and do from the web interface

Zenoss

Zenoss is a powerful, easy-to-use, open source IT systems monitoring and management product.

The goal of Zenoss is to provide an affordable, more usable, and open alternative to the big "enterprise management" suites.

GroundWork Monitor Open Source

GroundWork Monitor Open Source provides a complete entry-level availability monitoring solution to ensure IT infrastructure uptime while identifying issues before they become real problems. It is the first totally integrated IT infrastructure monitoring solution to deliver the basic functionality that systems administrators require in a free package.

Hyperic

Hyperic HQ features are packaged in a single, easy-to-deploy solution used by the most demanding data centers in the world. HQ consolidates common management tasks without sacrificing depth of manageability for any technology, enabling you to get better control over your IT infrastructure.

Zabbix

ZABBIX is software for monitoring of your applications, network and servers. ZABBIX supports both polling and trapping techniques to collect data from monitored hosts. A flexible notification mechanism allows easy and quickly configure different types of notifications for pre-defined events.

JNetControl

Management and configuring network equipment with support to Telnet protocol ie: Cisco tm, 3COM.