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System Center Operations Manager 2012 (SCOM) - SNMP device discovery

Lately I have been working in SCOM with SNMP devices. Needless to say I have learned some new tricks I would like to share with you.

Firstly you may have run into the dreaded "No response SNMP" message in Network Devices Pending Management in the SCOM console. First thing that jumps out is network connectivity, however I have seen cases that that is not the issue. Based upon my experience the message is very generic and could have several causes:

1. Network connectivity

 Firewall (on the SCOM server or one of the SCOM servers that is a member of the resourcepool specified in the discovery rule) or between the SCOM-server and the SNMP device.
    2. SNMP-device configuration

    The target SNMP device needs to enable the whole system MIB/OID-tree to be discoverable in SCOM. If any of the following OIDs are missing, you will not be able to discover the device:
    • 1.3.6.1.2.1.1.1.0 --> system.sysDescr
    • 1.3.6.1.2.1.1.2.0 --> system.sysObjectID
    • 1.3.6.1.2.1.1.4.0 --> system.sysContact
    • 1.3.6.1.2.1.1.5.0 --> system.sysName
    • 1.3.6.1.2.1.1.6.0 --> system.sysLocation

    3. SCOM host SNMP configuration

    Please follow microsoft recommandations on how to configure your SCOM server to be able to communicate with the SNMP protocol.


    Regarding network connectivity you have a lot of options. First on your list should be to temporarily disable the firewall and verify that you are still unable to discover the device with the firewall turned off. Next step should be to verify that the device is responding to ping requests. Further you should also verify SNMP UDP connectivity on port 161. There are a number of tools available for you to use. Paessler has an SNMP test tool (http://www.paessler.com/tools/snmptester)with a GUI and a console application you can use in scripts. Very handy if you need to add many devices and check if the device is on the certified SNMP device list from Microsoft. More on this later.

    Recently I have been experiencing issues with SCOM when there are no network connectivity issues and I have verified that SCOM is able to communicate with the device via SNMP. Time to get low, dirty and bring out the bag of tricks.

    First thing is to enable SNMP device discovery debug-tracing in SCOM. This is done in the file located in:
    C:\Program Files\System Center 2012\Operations Manager\Server\NetworkMonitoring\conf\discovery 

    and is called discovery.conf. Open the file in notepad and set the following:

    DebugEnabled = TRUE
    LogDiscoveryProgress = TRUE
    enableSNMPTrace = TRUE
    enableICMPTrace = TRUE

    LogDiscoveryProgress is not in the file, you will have to add it. Save the file and restart the healthservice on the SCOM server. You may use this powershell command:
    Get-Service –name healthservice |restart-service –verbose
    To be continued…
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    Comments

    1. AnonymousMay 6, 2016 at 6:59 PM

      Where is the "continued" post?

      ReplyDelete
    2. Tore GronengMay 6, 2016 at 9:09 PM

      Hi, sorry, it is one of the many things I have not yet been able to get to. Long overdue I admit.

      ReplyDelete
    3. UnknownJuly 20, 2018 at 12:16 PM

      Hi Tore,

      Have you forgot the continued post? :)

      ReplyDelete
      Replies
      1. Tore GronengOctober 29, 2018 at 2:35 PM

        hi, well kinda. The world have moved on to better things in the cloud. SCOM is not really something that I have been working on the last 2 years. Sorry, this will never be continued :-)

        Delete

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