SNMP doesn't work on one switch

Troubleshooting
1

Hi,
Getting SNMP data from one switch stopped working. I don’t see any services on it.

Setup -> Hosts -> Main directory -> Building -> Properties of host 10.10.2.1 -> Services of host 10.10.2.1
Full scan finished after 35.0 s at 2022-05-23 10:43:31. Found no services yet. To retry please execute a full scan.

OMD[monitor]:~$ cmk -D 10.10.2.1

10.222.1.1                                                                     
Addresses:              10.10.2.1
Tags:                   [address_family:ip-v4-only], [agent:no-agent], [criticality:prod], [ip-v4:ip-v4], [networking:lan], [piggyback:auto-piggyback], [site:monitor], [snmp:snmp], [snmp_ds:snmp-v2]
Labels:                 
Parents:                10.10.2.254
Host groups:            check_mk
Contact groups:         check-mk-notify, all
Agent mode:             No agent
Type of agent:          
  SNMP (Community: '****', Bulk walk: yes, Port: 161, Backend: Classic)
  Process piggyback data from /omd/sites/monitor/tmp/check_mk/piggyback/10.10.2.1
Services:
  checktype item params description groups
  --------- ---- ------ ----------- ------

Dashboard warning

no unmonitored services found, no vanished services found, no new host labels, [snmp] SNMP Error on 10.10.2.1: Timeout: No Response from 10.10.2.1 (Exit-Code: 1)

Before that, everything was working. SNMP working on switch.

Any ideas?

2

I’m not sure, but looks like SNMP isn’t working on your switch anymore. Or CheckMK can’t reach it. Were there any recent changes in your network? Can you ping 10.10.2.1 from your CheckMK server?

3

Ping from CheckMK is OK.
I can read snmp by snmpwalk on Linux.

4

An SNMP timeout also occurs when sending a wrong community string.

1 Like
5

Community is OK. I checked this.

I’m losing SNMP connection on this switch when I created CDP rule.

cdp_rule
cdp_rule817×879 96.2 KB

I have an error on dashboard:

no unmonitored services found, 134 vanished services (cisco_cpu_multiitem:1, cisco_fan:2, cisco_mem:2, cisco_power:2, cisco_stack:2, cisco_temperature:2, if64:119, pse_poe:2, snmp_info:1, uptime:1), no new host labels, [snmp] SNMP Error on 10.10.2.1: Timeout: No Response from 10.222.1.1 (Exit-Code: 1)
6

So if you remove/disable the cdp rule, then SNMP for this switch is working fine again?

7

Sometimes the SNMP communication comes back after the rule is removed.

8

this is a litle bit strange, as this rule has nothing to do with the way snmp works. Its a rule for one of my inventory plugins and will only change the content of the inventory…

have you checked this troubleshooting guide for SNMP?

9

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