OpsMgr: How to verify SNMP support in your network devices

Here are some tools, tips and resources to assist when SNMP device discovery or monitoring is not going as expected in Operations Manager (SCOM) and Essentials 2007.

Question: Discovery of my SNMP devices fails. How can I verify my device supports SNMP, and test device response before using in Operations Manager 2007 or Essentials 2007?

Answer: There are a number of resources you can use to determine what version of SNMP your device supports. You’ll need device IP and SNMP community string.

Checking SNMP version support

You can verify verify a device supports SNMP version 2c with the open source snmpget utility, which is part of the net-snmp tools. Download snmpget.exe and the accompanying mibs.zip file from the following URL and unzip to a local directory. Download HERE.

If you are not successful discovering your target network device, verify your device supports SNMP version 1 or 2c. To check, you’ll need the SNMP community string for your device, and the IP address with that of your target. Remember to replace IP and community string in the command below with those applicable to your environment.

snmpget -v2c -M D:\utilities\mibs -c public

Assuming the device has the required SNMP support, you should see output similar to the following:

SNMPv2-MIB::sysDescr.0 = STRING: 24-Port 10/100/1000 Gigabit Switch w/WebView

Note that the output will very by the device you are querying, change -v2c to -v1. If you still get no response, verify the criteria above and check with the device manufacturer to ensure your network device has the required SNMP support.


Reading the MIB

I get the mib from the hardware vendor. I then use MIB Browser 1.0 to view the OID tree. MIB Browser can be found HERE.

Another good MIB browser is the iReasoning browser, which is available HERE.

If the vendor cannot give me a mib, I check the MIB database at oidview.com to find the MIB for my device.



Polling a device for expected response

I then use iReasoning browser to perform a get on the OID to make sure it returns values as expected. I occasionally also use the snmpwalk utilities, which is part of the same tool set as snmpget.

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