The term "network monitoring" describes the use of a system that constantly monitors a computer network for slow or failing systems and notifies the system/network administrator in case of outages via email, pager or other alarms.
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.
uses developed-in-the-house network monitoring system which has been proven in industry as most reliable and flexible.