Since two weeks we're experiencing an odd problem. Around 4 o' clock all sensors or probes will drop all monitoring activity.
This phenomon could be explained if the devices went down, but they don't. All appliances remain active.
We see this drop for about 5 minutes, and all fonctions are restored after those 5 minutes. This drop is over the complete network (LAN, DMZ, ...) and on physical as well as on virtual machines. We even see a drop on the probe for our firewall.
Reports after the incidents show us just a blank spot for the 5 minute interval. We also see no particular increase or unusual behavior in any probes before the drop. (For exemple: a load too high could explain something)
Anyone has some pointers? Greatly thanks in advance.