I had an issue where at one of my remote offices an air handling unit was failing and the server room was heating up far beyond the recommended operating temperature. There were people working in that remote office, but I couldn’t rely on them to check on it daily and nobody was there over the weekends. I looked around and there were a few different devices and software products for monitoring temperature, but some were quite expensive.

I decided to play around and see if I could get a method working where I could monitor the temperature using something built-in and basic. I had read that most Dell servers have temperature probes that monitor air temperature for ambient air as well as planar (off the CPU/motherboard) and would make that available to the SNMP service specifically within the MIB-Dell-10892 specification.

I was surprised to find out how easy it was to set up SNMP and MRTG to poll the server and provide me with the readings I was looking for! Here’s how I did it:

First on the server, I enabled the SNMP service. It was a Windows server, so it was as simple as going to Start > Control Panel > Add/Remove Programs > Add/Remove Windows Components > Management and Monitoring Tools > [Details] > Select “Simple Network Management Protocol” to install it. Then to make sure there was a reasonable level of security, I went to the Services applet, found the SNMP Service and chose a READ ONLY community string and specified the IP of my monitoring host under the Security tab. I made sure the service was started.

Then I made sure to allow the UDP 161 and UDP 162 ports associated with SNMP were allowed through the firewall.

Next I put in the following settings into my MRTG configuration file. To tell you the truth, the hardest part was determining the calculation and syntax in order to get it to convert from Celcius to Farenheit!  Be sure to replace my IP and snmp community string with the IP and community string of your host in the configuration file settings.

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WorkDir: /var/www/mrtg
### Measure Planar and Ambient Temps
#—————————————————————
Target[10.1.100.100.temp]: 1.3.6.1.4.1.674.10892.1.700.20.1.6.1.1&1.3.6.1.4.1.674.10892.1.700.20.1.6.1.2:readonlycommunitystring@10.1.100.100 / 10 * 1.8 + 32
MaxBytes[10.1.100.100.temp]: 150
Title[10.1.100.100.temp]: Planar and Ambient Temperature – Remote Server
PageTop[10.1.100.100.temp]: <H1>Planar and Ambient Temperature – Remote Server</H1>
Options[10.1.100.100.temp]: gauge, integer, nopercent
YSize[10.1.100.100.temp]: 220
YTics[10.1.100.100.temp]: 11
YLegend[10.1.100.100.temp]: Temp degrees F
ShortLegend[10.1.100.100.temp]: deg F
Legend1[10.1.100.100.temp]: Temperature1
Legend2[10.1.100.100.temp]: Temperature2
Legend3[10.1.100.100.temp]: Legend3
Legend4[10.1.100.100.temp]: Legend4
LegendI[10.1.100.100.temp]: MotherBD Temp 1:
LegendO[10.1.100.100.temp]: Ambient Temp 2:
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