So a week or two ago we just got done ensuring all of our several dozen mikrotik site routers got upgraded to v7.14.2, most of them from v6.
A handful of our routers are also model CCR1009-7G-1C, but only one of those 1009's has developed an issue where it frequently refuses to reply to SNMP requests.
On its main IP it seems to change between accepting requests and not accepting them with a frequency between a few hours to several days at a time.
Creating different IP addresses and polling those sometimes works and sometimes does not, to the tune of each IP having it's own schedule of when it wants to work or not.
Changing SNMP settings does not appear to alter the pattern. EG, we normally run SNMPv3 with auth and priv but SNMPv2c behaves the same way.
CPU usage is constantly quite low.
Router has no firewall rules of its own, nor raw, mangle, etc. Application Layer Gateway services are all disabled except for the three that ROS7 does not allow you to disable: dccp, sctp, udplite.
IP remains accessible for ICMP and management traffic even while SNMP is out of service, and every other function that we use the router for shows no other signs of trouble.
So what would you try or test next if you were in this situation?
