Technical Tip: Configuring SNMP communities for HA mgmt and Root vdom loopback

In FortiGate SNMP configuration, the ha-redirect needs to be enabled so that can reach the HA mgmt interfaces:

config system snmp community
    edit 3
        set name "public"
            config hosts
                edit 1

                FortiWiFi-home (1) # set ha-direct
                enable Enable setting.    <----- Use the vsys_hamgmt routes.
                disable Disable setting.  <----- Use the root routes.

The below log will indicate the interface changes in 'dia deb app snmpd -1' when ha-direct enabled:

snmpd: Successfully removed interface operation status file: /tmp/snmpd.intf_op_info
snmpd: updating cache: idx_cache

It will cause issues if the same SNMP server queries other interfaces, such as loopback in the default Root VDOM. It is necessary to create multiple SNMP communities for the same SNMP server so that it can inquiry HA mgmt and loopback interface: