Network Performance Monitoring

These are the questions asked during Network Performance Monitoring Training


  • Is there any way to find out the name and location of the person who is using too much bandwidth or can we only find the IP address? OpManager uses SNMP to fetch Interface details. Using Netflow Add-on which is flow based we should be able to track the usage based on IP.
  • What type reports can I get on traffic monitoring?You can get Intraffic and OutTraffic report, Utilization report, and report on Errors and Discards.
  • Why should we re-discover a device?  You should rediscover the device if there are any additional changes in the device, for example if you replace the device RAM from 2GB to 4GB and you want to see the same in OpManager, you can rediscover the device and see the new RAM details in OpManager, likewise it is applicable for all device properties.
  • How to disable receiving specific traps of few devices in OpManager? We can create a specific customized SNMP trap processor that matches the incoming OID and then select the option to ‘Disable’ when created. This would avoid the un-necessary traps that are received in the application or from a specific device. 
  • How to ignore specific error conditions like 'attention'/'trouble'/'critical' for a specific device so that alarms don't get generated for the specified condition of that device ? You can un-check the option provided at the bottom of the Notifications page that would have an option to select "Attention", "Trouble", "Service down", "Critical", "Clear" etc. Once when you uncheck this option, you will be provided with an option to send emails based on severity. 
  • What are vendor MIBs? Cisco devices supports Cisco MIBs’ which are provided by cisco vendor. Similarly, other vendors also have their own MIBs.
  • How is Total traffic utilization calculated ? In-traffic utilization per sec = ( InOctet * 8000 * 1000 * 100)/Delta time
    Out-traffic utilization per sec = (OutOctet * 8000 * 1000 * 100)/Delta time.
    Total traffic utilization = In-traffic + Out-traffic
  • Is it possible to generate a weekly or monthly uptime report of a particular interface when my ISP is terminated ? Uptime report can be generated in interface snapshot page. Click on the interface name in device snapshot, and click on Availability dial to generate uptime report.
  • How to import and use a MIB file in .txt format for Sophos XG firewall in OpManager? You can copy that MIB file to OpManager\mibs directory and load it using MIB browser to identify the OIDs that are used for monitoring performance of the firewall. Once you have the OIDs, you can create a custom template for the device in OpManager. To know more about device templates, refer this page: http://help.opmanager.com/device_templates_api-v12
  • Is it possible to add a Blue Coat device in OpManager?  We have few templates readily available in OpManager for Blue Coat Wan Accelerators as well as Switches. If you are looking for a template for some other new Blue Coat device, we have to get the required MIBs/OIDs from vendor and add a custom template in OpManager. Learn more about creating device templates here : http://help.opmanager.com/device_templates_api-v12
  • How can we monitor Riccoh printers using OpManager ? You can monitor the Riccoh printer by creating a custom device template and then creating performance monitors. Please check the below link to know more about creating a device template in OpManager: http://help.opmanager.com/device_templates_api-v12
  • We use a device called NetBox Blue by Cyberhound which is software-based firewall. What is the best way to add and monitor a virtual appliance running in VMware?You can monitor NetBox Blue Firewall by creating new device template and associating a performance monitor in the template. Also, make sure you enable SNMP in the Firewall. Learn more about creating device templates here: http://help.opmanager.com/device_templates_api-v12
  • Will it monitor an exchange/Office 365 hybrid environment?OpManager can to Exchange servers. For Office 365 monitoring, we recommend APM plugin.
  • Is file monitoring only available for Windows?Yes. Since it is limited to WMI, it is available only for Windows.
  • Nutanix runs in a CentOS environment, would it be able to monitor that?We can monitor if it responds to SNMP OID. As per this link, we can configure SNMP and add few metrics. Please refer this video and contact support for further assistance.
  • What is exactly total traffic for an interface ? Is it the total traffic from the specific point in time until another point in time?It is based on the polling interval. If Interface polling interval is 15 mins, then the last polled value is the traffic in between the two consecutive polls.
  • How can I know the total amount of traffic through an interface from time 1 to time 2 ? Is there a report?You can choose the time period in reports and pull the data based on this.
  • Is it possible to make a script run from a specific device instead of the monitoring server and I'm talking here about Microsoft windows devices?For Windows devices, script has to be executed locally but there is are workarounds like psexec(third party) or an option in Powershell where a block of code can be executed on a remote server. This psexec or Powershell script might run locally on windows server but it can call the remote script or run the block of code on a remote server.
  • What should I do when I discover a vCenter and in "virtual details" it shows the esxi host, but it doesn't start monitoring automatically? DNS records are correct. How can I force start monitoring it?  Rediscovering vCenter, deleting and readding vCenter doesn't help alsoYes it won't help, as DNS name is not updated so deleting and rediscovery will again do the same thing. But if do update the dnsname then in the next scheduled discovery of vCenter, it will automatically start monitoring the corrected ESXServer

    If you correct the DNS Records it would be great, but in case its not correct you can force start monitoring by going to vCenter snapshot page -> Host List Widget and in the end there is Monitoring Column, from there on you can give IP and start monitoring it. Also, in our next releases we are going to do away with DNS Name dependency we are going to rely on the Entity Name only.
  • I have 6 ESX host, however one doesn't show up under Virtualization / VMware-Host. How do I add it to that section?That section only shows the monitored ESX Server's. You can go to vCenter snapshot page and see the complete list of ESXServers mapped to that vCenter.
  • Why does SNMP write have to be enabled for IPSLA?OpManager need to push the IPSLA settings on the network device using SNMP write.
  • What permissions are required by the vmware vcenter credentials?HTTPs credential for VMware vCenter with ReadOnly Permission are enough to monitor vCenter.
  • What is the quickest/easiest way to identify against which IP or interface the DOS attack is against from my main router, I am also using your product netflow?In NetFlow, you can see the source IPs in 'Offender' tab under attacks event drill down. You can see about the interface details under 'Field Details' tab (Unique IN interfaces and Unique OUT interfaces) under attacks event drill down.
  • What happens if the OpManager Server Hard Disk goes full, how can we free Space on Server?NFA specific hard disk space usage reduction can be done by setting proper data retention period under Settings->NetFlow->Storage Settings.
    Data retention period for Raw data , Aggregated data and One Min data can be set there.
  • If someone DOS attacks me, how can i see the network utilization in for example last 3 minutes to solve the problem quickly, not in last 1hour. If I view it in last 1 hour then its very hard to notice the massive peak in my network.- Note down the Offender IP and Interface name from attacks drill down.
    - Go to Reports -> Custom Search Reports
    - Select that interface and give the offender IP value for 'Source Address' criteria and select the desired time frame.
    - Click 'Generate report'
    - If Raw data is enabled , then more detailed report can be seen under Reports -> Forensics Reports
  • What constitutes a license for a monitored device? i.e. = Physical Server / Virtual Host (HYPER-V)? –> Virtual Machines?The license for a monitored Virtual Host or Virtual Machines are same as Physical Server. There is no difference in it. One Device - One License.
  • How can we monitor VPN connections in a Cisco ASA and create a view of this?You can create your own monitors for SNMP-enabled devices, detailed steps are available in this link: http://help.opmanager.com/add_custom_monitors_api-v12
  • Do you provide updated or new device templates, especially network templates in the ManageEngine Portal?We have a dedicated user community who share templates on a regular basis. You may send us an email and we shall help get this done. We will also share you the community link.
  • As we get the string value from SNMP, can we have Devices Serial Number in devices snapshot page using SNMP Response Value? Sorry, custom dial is not supported for string monitors for now. We are going to track the OID response and show it as a custom field value in device snapshot page in future.
  • How to configure bulk bandwidth RX And TX bps for particular group of interface , (For Eg: we want to make all Ethernet interface as 2 Mbps.. or 4 Mbps). We can configure IN/OUT speed via Device snapshot > Configure interface for Switch and Router devices.
  • Is VoIP monitoring supported only on Cisco devices?Yes.
  • Are Device templates available for Cisco Switches - Cisco 3850 Firmware 3.7.4, IOS-XE Please create this using custom template option and share the OID list to OpManager support, we will integrate this in our future releases.
  • How to schedule Switch Ports Utilization Report on OpManager? We have all Interface Utilization reports under Reports -> Health and Response. You can schedule the reports here.
  • While monitoring via ICMP and TCP, when TCP is selected, it asks us for a port - which port number should we assign? You can assign a port which open in the device, so OpManager will telnet into the port and if the port is available then it considers the device as available.
  • Can we set Latency Threshold parameters for each monitor instead of from a template? - In IPSLA Protocol It's not possible currently. We wiIl take it as a requirement, look into it and try bringing it into the product.
  • Do hardware sensors support Palo Alto firewall ? As of now, it is not supported.
  • Where is the backup of the devices saved? OpManager does not save the device backup. NCM will save and store it in the database.
  • Is there any future is available in OpManger that should able to collect data from all components monitoring in azure? Yes, We have this feature in our roadmap.
  • When using Dell N3024F Switch , I am getting alarm network interfaces is 94 nos threshold value for this monitor is 85 nos. Why is this happening? It means that the number of interfaces exceeds 85. Please query ifNumber in MIB Browser to check the number of interfaces. If you don't need alarm, you can disable the threshold for the monitor.
  • What is the meaning of network interfaces for a switch and how does this value reach the threshold value? The Network interfaces means that total number of interfaces available in a device. When the network interface count increases, If we have configured threshold, We will generate alarm. It is purely based on SNMP.
  • Even though the Firewall is monitored, the dashboard does not show the CPU usage and memory usage. Why? This could be happening as the data collection for the respective monitor on the device would have been happening. The cause for this could be that credential is failing or device is not responding to the respective OIDs.
  • What is the performance of discards? Discards means the number of inbound/outbound packets which were chosen to be discarded even though no errors had been detected to prevent their being deliverable to a higher-layer protocol. One possible reason for discarding such a packet could be to free up buffer space.
  • Does Licensing depend on number of devices monitored or the number of performance monitors? Licensing depends on Number of devices are monitored in OpManager. Performance monitors will not be considered for Licensing.
  • In the OID browser, is that value is already exist on there, or is it entered or imported manually ? By default, the OID value will be there. we just need to select the OID. We can also enter it manually too.
  • What is OID? An OID is a globally unique ISO identifier. There are multiple ways that this identifier may be represented, and HL7 has chosen to represent OID registered here and used in HL7 models using a form that consists only of numbers and dots (e.g., "2.16.840.1.113883.3.1"). It is used for monitoring the performance of a device.
  • What is MIB files ? MIB files is a collection of OIDs which are defined by the device vendor. These OIDs will give performance metrics values from the device.
  • On network maps, Can we customize the global map without country name? In Business view you can import custom image without country name. In Zoho Maps you drag the devices to the respective country.
  • What is OpUtils? OpUtils is a IP address and Switch port management software that is geared towards helping engineers efficiently monitor, diagnose and troubleshoot IT resources. OpUtils complements existing management tools by providing trouble shooting and real-time monitoring capabilities.
  • Can you import custom back grown images for the map? We can't import custom background images for map. But, we can do it in Business view. To be precise, yes you can import background images by clicking on Maps-->Business Views-->Create New business view and you will see"selct background image".Hope this helps.
  • can you share how to setup snmp on vmware host so i can monitor in OpManager? I think Vmware technicians are the right guys to help you with step by step instructions on enabling SNMP on Vmware host.once you enable SNMP on those,you can discover and start monitoring.Hope the below link helps, https://www.manageengine.com/network-monitoring/help/vmware-discovery.html.
  • I thought Cisco IPSLA required a customer to modify the device configuration. Is OpManager automating this process with a standard set of monitors? We can monitor IPSLA using standard set of monitors like Availability, RTT, etc... Please check this like for IPSLA monitor addition https://www.manageengine.com/network-monitoring/help/add-new-wan-monitor.html
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