Network monitoring

The term network monitoring describes the use of a system that constantly monitors a computer network for slow or failing systems and that notifies the network administrator in case of outages via email, pager or other alarms. It is a subset of the functions involved in network management.

While an intrusion detection system monitors a network for threats from the outside, a network monitoring system monitors the network for problems due to overloaded and/or crashed servers, network connections or other devices.

For example, to determine the status of a webserver, monitoring software may periodically send an HTTP request to fetch a page; for email servers, a test message might be sent through SMTP and retrieved by IMAP or POP3.

Status request failures, such as when a connection cannot be established, it times-out, or the document or message cannot be retrieved, usually produce an action from the monitoring system. These actions vary: an alarm may be sent out to the resident sysadmin, automatic failover systems may be activated to remove the troubled server from duty until it can be repaired, etcetera.

Software used in network monitoring

• The ping program
• Big Brother
• Caligare Flow Inspector
• MRTG
• RRDtool
• Intellipool Network Monitor
• PRTG
• SNMP servers
• AdRem NetCrunch
• Nagios (formerly Netsaint)
• ManageEngine OpManager
• Cricket
• IPCheck
• Ipswitch WhatsUp
• Packet Analyzer: Network Traffic Monitoring, Analysis and Troubleshooting
• Network Management Systems
  • HP OpenView Network Node Manager (NNM)
  • IBM Tivoli Netview
  • OpenNMS
  • Infosim StableNet

See also

• Intrusion detection system
• List of network management systems