State Stalking is a very useful feature. Though all the users do not use it all the time, it is very helpful when we want to investigate an issue.
In State Stalking, we can enable stalking on a host. Nagios will monitor the state of the host very carefully and it will log any changes in the state.
By this we can identify what changes might be causing an issue on the host.Read the full book at www.amazon.com