receving phantom downtime

Hi

I am running opmanager in parallel with the old monitoring system.

Over the past 3 days, we have had 2 bogus alerts generated for servers being down, for 3-7 minutes at a time.

One was for server not responding (icmp) and the other for a port not being available.

Investigation of the old monitoring system, which is icmp based, shows that teh server was available during the time were opmanager said the device was offline, and there was no user interruption to correspond with opmanagers reported outage.

I installed a hotfix today that let me set ping timeout, it is now set at 5 seconds.

Can you shed any light on this, as we dont want continuing false positives.

Thanks
Dave