With IPHost Network Monitor you can run simple snmp requests against a Fortinet device in your network.
fgHwSensorEntValue
fg Hw Sensor Ent Value
1.3.6.1.4.1.12356.101.4.3.2.1.3
A string representation of the value of the sensor. Because sensors can present data in different formats, string representation is most general format. Interpretation of the value (units of measure, for example) is dependent on the individual sensor.
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IPHost Network monitor allows you to monitor fgHwSensorEntValue on Fortinet device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Fortinet switches right now.