I think I may have stumbled upon a bug in low level discovery.
On a Cisco 2811 router and on a 4948 switch, when regular SNMP item checks are set up in the usual way, SNMP queries to those devices work perfectly fine.
If I set up low level discovery to the router, from what I can see in the zabbix_server.log, a bunch of timeouts on SNMP items leads to the item being disabled.
From what I can see, it looks to me as though the SNMP timeout value is being ignored, and one second timeouts are causing the issue.
NETWORK_ERROR in the zabbix_server.log and "Timeout connecting to [IP]:[161]" in the Zabbix web frontend (when I mouse over an item that has disabled itself) are symptoms of what I'm seeing.
Again, if I build SNMP ifOutOctet and ifInOctet items by hand "the old fashioned way" I never see these issues, and snmpwalks against both devices work perfectly fine (I use '-t 3' to set the timeout for snmpwalk)
See also https://support.zabbix.com/browse/ZBX-4393 - I'm on Linux though. The symptoms look exactly the same as what's reported on ZBX-4393.
Possibly the version of net-snmp I'm using is the underlying culprit? I understand Zabbix uses net-snmp's libs and API to do its SNMP checks.
On a Cisco 2811 router and on a 4948 switch, when regular SNMP item checks are set up in the usual way, SNMP queries to those devices work perfectly fine.
If I set up low level discovery to the router, from what I can see in the zabbix_server.log, a bunch of timeouts on SNMP items leads to the item being disabled.
From what I can see, it looks to me as though the SNMP timeout value is being ignored, and one second timeouts are causing the issue.
NETWORK_ERROR in the zabbix_server.log and "Timeout connecting to [IP]:[161]" in the Zabbix web frontend (when I mouse over an item that has disabled itself) are symptoms of what I'm seeing.
Again, if I build SNMP ifOutOctet and ifInOctet items by hand "the old fashioned way" I never see these issues, and snmpwalks against both devices work perfectly fine (I use '-t 3' to set the timeout for snmpwalk)
See also https://support.zabbix.com/browse/ZBX-4393 - I'm on Linux though. The symptoms look exactly the same as what's reported on ZBX-4393.
Possibly the version of net-snmp I'm using is the underlying culprit? I understand Zabbix uses net-snmp's libs and API to do its SNMP checks.
Comment