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Home > Success Center > Network Performance Monitor (NPM) > NPM - Knowledgebase Articles > F5 virtual servers sometimes go into unknown status

F5 virtual servers sometimes go into unknown status

Updated October 5, 2016


F5 Virtual Servers may go into an unknown status when polling them using NPM 12.0 or later that contains new F5 pollers.


NPM 12.0 and later


Potential device issue.


To determine if this is also a device issue, you should capture an snmpwalk as follows:

    1. Choose one of the nodes, where the issue is usually visible.
    2. Ceate advance alert for selected node that will trigger when the issue appear (F5 virtual servers go into unknown).
    3. Set up the wireshark Capture Options:  - Capture Filter: udp port 161 and host <selected node IP_address>  - specify .File name  - select "Next file every" and specify the file size  - select "Ring buffer with" and set the value to 2.
   4. Start capturing.

   5. When the alert is triggered, both pcaps.

   6. In the .pcap file you can may find that we don't get response when we ask for an OID such as

   7. Since we need the results from this OID and others in the poll, the whole poll will be marked as timed-out. It may not only this OID but it maybe that the device does not respond for a while on all our requests.

Steps to check for no response from device
  1. Open the pcap.
  2. Set filter ip.addr==X.X.X.X (IP of device).
  3. Sort the results by time.
  4. If there is no response from Date Time to Date Time of issue.
  5. You should send these on to the vendor, F5 for investigation as SolarWinds support will confirm with such findings that this is a device issue..


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