Tuesday, February 28, 2012

Network Devices not discovered?

Today a customer of mine run into an issue when he wanted to discover network devices with SCOM 2012. So he added the devices to the explicit discovery rule and started the discovery process immediately.

After a while he checked for the new devices in the Network Devices view (Administration, Network Management, Network Devices) and was not able to see them in this view.

So he double checked the devices in the discovery rule and started again – same problem.

As it seems, the devices are excluded from the discovery. To check that we had to export the Network Discovery Internal MP (unsealed). After that we opened it with a XML or Text editor and went <ExcludeIP> tag and usually the IPs are listed there. (Be aware that there might be several rules and each has its own exclude- list!)

We simply removed the whole line with the device IP, increment the MP version number and import the MP again.

Now we ran the discovery rule again and after a while the devices occur in the view as mentioned above.

At this time we where not able to reproduce the matter for this behavior but I assume that the devices had been deleted manually in SCOM during the testing phase what will put them into the exclude list (to be sure that they won’t be discovered again by accident).

Note: for easier following the discovery process you can filter the Operations Manager log for source OpsMgr Network Discovery. Event ID 12008 includes a summary and there you can check for the number of discovered devices as well as for the amount of excluded ones.

Update: when using Recursive Discovery (= auto-discover) you can remove those devices in the wizard of the discovery rule as well. Find them in the Exclude Filters page within the discovery rule properties.

All information is provided "as is" without any warranty! Try in lab before. Handle with care in production.


  1. Where do i find this Network Discovery Internal MP (unsealed)

  2. Hi Eri!

    You find the MP already in your SCOM 2012 Management Group in the Console under Administration, Management Packs.


  3. Thanks Patrick,
    I already found that MP after i asked. Kindly help me here instead.
    I could not find the tag and all the 5 computers i dicovered are FILTERED OUT. please help. am i have a dead line on this project. find part of the event .
    Date and Time: 3/1/2012 9:12:05 AM
    Log Name: Operations Manager
    Source: OpsMgr Network Discovery
    Generating Rule: Detailed Network Discovery Events
    Event Number: 12008
    Level: Information
    Logging Computer: SCOM2012RC.fidelitybank.com
    User: N/A
    Discovery Completed

    Devices discovered: 0

    Windows computers filtered: 5

    Devices in pending list: 0

    Devices excluded: 0

    Duration Total (sec): 9

    Duration of Probing (sec): 9

    Duration of Processing (sec): 0

    Workflow name: discovery8a257421.74eb.4589.8454.bea9c6bc4d37

    Instance name: SCOM1

    Instance ID: {21C59F6E-1FAB-E566-891B-A881C7835D1D}

    Management group: FideFirstOperationsMagGroup

  4. Hi Eri!

    As it seems, the devices are filtered out, not exlcuded:
    Windows computers filtered: 5

    Do you use Recursive Discovery? If so, go to your discovery rule and check the Include Filters. Also, when using Recursive Discovery you can modify the Exclude Filters within the wizard.


    1. Acctually Pat thats the problem.
      i never used recursive/ filtering in that initial discovery. I rather used Explicit and those 5 systems where specifically selected for that discovery.

      Any way we can resolve this?

    2. Pat,
      Its obviouse the exclusion was delibrate from Microsoft. see this link http://technet.microsoft.com/en-us/library/hh212935.aspx

      My question is how can i get scom2012 to undo this setting and include those computers as i actaully want to monitor computers usings SCOM2012 SNMP CAPABLITIES

    3. Hello Pat.
      I think u need to c this.
      how can we work arround it cos i think its at play here.


  5. Eric,
    unfortunately I can't figure out what part of the documentation you mean.

    Can you send me the MP mentioned in my blog above? Contact me through http://www.systemcenterrocks.com/p/contact.html and then I'll send you my mail address.