With IPHost Network Monitor you can run simple snmp requests against a D-Link device in your network.
swFanSpeed
Switch Fan Speed
1.3.6.1.4.1.171.12.11.1.7.1.6
Indicates the fan work speed(RPM).
Back to EQUIPMENT-MIB MIB page.
IPHost Network monitor allows you to monitor swFanSpeed on D-Link device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring D-Link routers right now.