Mikrotik SNMP strange behavior

gorbushka · Tue Jul 13, 2021 3:45 pm

Mikrotik cAP 2nd
RouterOS firmware 6.48.3

There is a strange snmp behavior when i'm trying to get metrics via snmp_exporter. The exporter responds snmp error:

error collecting metric Desc{fqName: "snmp_error", help: "Error scraping target", constLabels: {}, variableLabels: []}: error walking target 10.254.250.101: request timeout (after 3 retries)

Then i got tcpdump with this request-response exchange. And I saw that wireshark marks some responses as malformed packet with

"BER Error: Wrong field in SEQUENCE OF: expected class:UNIVERSAL(0) tag:16(SEQUENCE) but found class:UNIVERSAL(0) tag:1"

etc...
The error has occurred after request mtxQueueTreeName but in response Routeros trying to send ip neighbors.
There is also strange because i never trying to get ip neighbors via snmp.

Then I try to disable IP neighbor discovery and this fix my problem with snmp_exporter.

dump in attach