Using the Dude 3.4 we monitor a mix of VPN connected RB’s and public Internet connection RB’s.
To clarify, the issue we have is not directly related to V3.4 of the dude, it was happening on 2.x as well before we upgraded.
When monitoring a VPN connected RB, all SNMP requests work correctly, in the majority of cases anyway, all we do as add our SNMP community to the list with the IP of a management server in there, all good.
When we try to monitor a public internet connected RB we get no SNMP response, no matter what we do, no firewall rules, no restrictions on SNMP, etc, full access, and we get ZIP from the SNMP on the RB, not one thing. We can get all the ROS info fine.
When we setup a VPN to that box, SNMP works straight away !
Can anybody suggest what might be going on here, it’s strange, it certainly looks like a firewall type issue, the only thing I can think is something something funny is happening to the SNMP packet when it comes back, or something strange. When I check the connection table on the RB which is internet connected, it shows no connection to port 161 on the router, yet the public IP of the management box can do everything else, telnet, ssh, winbox, etc, it’s not an access issue.
Thanks for your help
Regards
Paul