Appendix B. Rapidly Alternating States: Flapping

If the state of a host or service keeps on changing over and over, Nagios inundates the administrator with a flood of problem and recovery messages, which can not only be very irritating but also distract the administrator's attention from other, perhaps more urgent problems.

With a special mechanism, Nagios quickly recognizes alternating states and can inform the administrator of these selectively. The Nagios documentation refers to such alternating states as state flapping and to their detection as flap detection.