Nagios Support Forum

We are using NagiosXI (2009R1.2) for monitoring some switches. A switch went down and nagiosxi showed this link as still up and didn't send any feedback or email.
I checked the configuration, host IP address and other configurations of that host and they are correct.
I monitored this link in nagvis as well and in nagvis this link shows as up instead of down (Green Light and 1.4 ms ping time).
This monitoring system usually works fine. Whenever a host goes down nagiosxi shows it as down and the host color in nagvis changes to red and nagios sends an email alert.
After removing and adding the host everything works fine.
Any advice on why this failed?

Can you duplicate problem? How long was it down for?

And I also see you are running a very old version of Nagios XI, have you considered updating? We're currently on 2011r1.5 and its very stable, and with minimal fuss, all it will ask is for is your activation key again, other than there aren't any update pains.