Fortinet Switches and Zabbix cannot read from session: Bad parse of ASN.1 type

[Vercham]

Hello,

I have Zabbix 7.0.9, which I use to monitor my switches. I am using SNMP agent and configured SNMPv3. This then gathers all the data that I need, however after a while net.if.walk stops gathering data and gives the error "cannot read from session: Bad parse of ASN.1 type". All other data is still being gathered like CPU util, mem util, etc. If I use the test function on net.if.walk it is able to get the data. I tried switching to SNMPv2c but this didnt change anything.

Does anyone know why this might be the case?

Many thanks

[AdriGallego14]

Hello, I'm running into the exact same issue with my device (a PLC) and was wondering if you ever found a solution.
I suspect my device is sending a malformed SNMPv3 response packet. It would be incredibly helpful if you managed to capture a successful response and could share the Wireshark capture.
I'm specifically looking for the initial discovery packet NoAuthNoPriv where the SNMP agent sends back its EngineID (usually in a report PDU). This would allow me to compare the ASN.1 structure of a known-good response with the one from my PLC to find the error.
Any help would be greatly appreciated.