My Cisco SG500-28p Switch SNMP availability unstable

[zaki4594]

Hi,
First of all, I want to inform you guys that I'm a beginner in this kind of thing. So the thing I wanted to do is to monitor my Switch by using snmp. I already unblock the access to the switch (port 162, 161) in my PFsense router so that Zabbix can reach it. I also verified the details like SNMP community and version are correct.

However, the problem is when I launch Zabbix, the state/availability of the SNMP is changing or should i say unstable. It was like in the first 10 minutes it was green and then the next 10 minutes it was red and it repeats the same thing again and again (see the images attached). I couldn't figure out what the problem is. Can someone lend me a hand please ? Thanks in advance

[allexpetrov]

Hi Zaki,

Please make sure you don't have problems with your networking. I can suggest you to:

Digg through the logs in your PFsense. Zabbix is utilizing Bulk Get requests for SNMP(by default) and sometimes this approach the thing that SNMP target don't like. You can change it in the host interface setup. This one is valid only if your PFsens acts as a router between Zabbix and Switch. If they are directly connected - investigate your switch.

Regards,
Aleksejs!

[zaki4594]

Hi allexpetrov and thank you for the reply,

I did a digging on the log files, so this is what I found. In my Zabbix server log, i got this kind of error:
"cannot send list of active checks to -@IP- host [PfSense-ASII] not found"

In my switch, I got this :
ASII-SW#14-Dec-2017 15:00:52 %SNMP-W-SNMPAUTHFAIL: Access attempted by unauthorized NMS, aggregated (3)

I already tried to uncheck the bulk request, but nothing changed. Based on the error I got from the log files, I think there's some problem but i don't know where it came from. Any idea?