Hello,
Scenario :
85 Cisco switches
80 sites
Several firewalls between SW server and devices
SNMPv3
I had a problem several weeks ago. From time to time, some devices (totally random) started to have a blinking icon with a litte grey square. I realized then that all interfaces switched to "unknown" state. I use SNMPv3.
I could "List ressources" from the web interface on those devices...so that prove the snmp connection works !
But I COULDN'T do it in the System Manager (with an error about SNMP credentials not correct (that was not the case)).
The ONLY way to resolve the problem was to delete the device and add it again.
I extend the SNMP request time out to max (5000ms).
Never had the problem again...since today. I added 5 new devices 4 days ago. They were working fine since this morning. All of a sudden, the little grey square appear again with unknown interfaces.
I did some network packet sniffing and I realize that when a device starts having this problem, the polling engine try to connect to the device using SNMPv2 and community name PUBLIC (remember I use SNMPV3 with user/password). This is odd because all SNMP settings weren't changed. I took a look directly in the database too and SNMP settings are exactly the same for all devices.....I really don't know where this SNMPv2/Public settings comes from.
I'm really out of ideas right out. Anyone has the same problem ?
thank you