I think D) polling interval set to value other than default could also be a cause. If the interval is too long, it might show the nodes as down even when they are up.
Definitely A and C. I've seen this happen before when the monitoring setup wasn't configured properly. Gotta make sure those SNMP details are on point.
A and C seem like the most likely culprits here. ICMP being blocked would prevent the status checks, and incorrect SNMP creds would cause the nodes to appear down even when they're up.
I agree with Lorenza. If the ICMP is blocked, the polling engine won't be able to communicate with the nodes. And incorrect SNMP credentials would also prevent proper communication.
Marnie
2 days agoAlex
5 days agoShannan
10 days agoMartina
2 days agoFelicitas
13 days agoCecil
3 days agoMicaela
4 days agoWendell
13 days agoLorenza
18 days ago