Troubleshooting polling issues can involve many steps and there are a few quick things we can try first before placing a support call. For example, say we have a piece of networking equipment such as a router or switch that is being monitored in Orion and suddenly the interfaces go unknown (gray) on the network device. This is telling us that SNMP information is not being recorded for the interfaces. More than likely we will not see any CPU or Memory utilization being reported either. To troubleshoot this issue we can do the following.

  1. Verify that the network device is configured correctly for sending SNMP traffic to the Network Management Software. A quick example would be verifying that the community string is correct.
  2. Run a packet capture on the server hosting the Network Management Software. We can poll the device from the Orion website by selecting “poll now” from Node Details. This sends SNMP (UDP 161) traps to the destination network device. While you are polling the device, run a sniffer trace using a program like or similar to Wireshark (formerly Ethereal). If there is a network issue, you will see SNMP frames leaving your Network Management Server, while no response is returned from the network device.
  3. If you do see frames returning from the network device, then this rules out network connectivity issues. Next verify there is no firewall blocking the SNMP frames on the server hosting the Network Management Software. If you are running a sniffer such as Wireshark, the incoming frames are being read at the Network Interface Card. A local server firewall such as Windows Firewall can still block SNMP frames from reaching the Network Management Software even though we see them hitting the NIC card. Note also that if a firewall is blocking SNMP traffic on the local server this will prevent any SNMP related information from being reported in your Network Management Software.

In summary verifying end to end connectivity between the Network Management Server and the device in question is the key and there are a few steps we can do to verify and possibly fix polling issues saving the end user some time.