Hey @SlothSlayer ,
Keep in mind that there's two different sections for SNMP depending on whether you are polling internally in the network or externally from the internet.
As you mentioned the WAN setups, I assume you are polling remotely, in which case you are looking at the Organization wide setting:
https://documentation.meraki.com/zGeneral_Administration/Monitoring_and_Reporting/SNMP_Overview_and_...
Remember that you are actually polling the information from the Dashboard and not directly the MX (hence the target being snmp.meraki.com ), although if you have allowed it, you should be able to carry out continuous pings to the MX.
Also, remember to put the IP address you are polling from in the Allowed list.
The Network-wide setting is useful only when you are polling internally from the LAN.
If you are still having trouble, try following the testing steps here and see what you get:
https://documentation.meraki.com/zGeneral_Administration/Monitoring_and_Reporting/SNMP_Overview_and_...
Hope this helps!
Giacomo
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