Thanks for the reply. I meant there is no events generated in my zenoss core 4.2.3. For example, If i shutdown a server which is monitored by two zenoss core currently(one is 4.2.3,another is 3.0.3), an "ip x.x.x.x is down" event will be generated in my zenoss core 3.0.3, but will not be generated in 4.2.3.
Thanks in advance,
Sheng