How to discover network devices in Operations Manager
Important
This version of Operations Manager has reached the end of support. We recommend you to upgrade to Operations Manager 2022.
System Center Operations Manager performs network discovery by running discovery rules that you create. Each time the rule runs, it will attempt to find new devices within its definition or changes to devices that were previously discovered.
Note
Discovery of a large number of devices can take several hours to complete.
Each management server or gateway server can run only one discovery rule. You specify a single management server or gateway server to run the discovery rule and a management server resource pool to perform the actual monitoring of the network devices. If you plan to monitor more than 1000 network devices, you should use two resource pools and split the number of devices evenly between the pools.
Note
If you create discovery rules on multiple management servers, you should create a management pool for each and ensure that each discovery defines a different set of devices. If a single device is managed in different pools, it won't be able to be deleted.
Prerequisites
To create a network devices discovery rule, you need the following information:
The IP address or FQDN of each device that you want to discover and monitor.
Note
Operations Manager can identify connected devices in a recursive discovery that use an IPv6 address; however, the initial device that's discovered must use an IPv4 address.
The version of SNMP that each device uses. This can be SNMP v1, v2, or v3.
The SNMP community string of each SNMP v1 or v2 device that you want to discover and monitor.
The user name, context, authentication protocol, authentication key, privacy protocol, and privacy key for each SNMP v3 device that you want to discover and monitor.
If you're using recursive discovery and you only want to discover network devices that have interfaces whose addresses fall within a specified IP address range, you must have the IP address range.
The name of the management server resource pool that will monitor the discovered devices.
Note
When Network Load Balancing (NLB) is used, the destination MAC address for the network adapter (cluster adapter) uses the format of 02-BF-1-2-3-4 and the cluster hosts use a format of 02-h-1-2-3-4, where h is the host's priority within the cluster (set in the Network Load Balancing Properties dialog box). Operations Manager will create a network connection between the devices using 02-h-1-2-3-4 to the destination MAC address of 02-BF-1-2-3-4.
Firewall configuration
You must ensure the following firewall configuration before creating the network devices discovery rule:
All firewalls between the management server and the network devices need to allow SNMP (UDP) and ICMP bidirectionally, and ports 161 and 162 need to be open bi-directionally. This includes Windows Firewall on the management server itself.
If your network devices are using a port other than 161 and 162, you need to open bidirectional UDP traffic on these ports.
Important
Note for customers who used EMC Solutions for Microsoft System Center Operations Manager: EMC Smarts included tools to create an isolation layer to prevent denial of service attacks. In System Center - Operations Manager, you need to protect your network against packet storms by using external tools.
To create a network devices discovery rule
Open the Operations console with an account that's a member of Operations Manager Administrators.
In the Administration workspace, right-click Administration, and select Discovery Wizard.
On the What would you like to manage? page, select Network devices, and select Next.
On the General Properties page, do the following:
In the Name box, enter a name, such as My Network Devices.
In the Available servers dropdown list, select a management server that has access to the devices you're discovering to run the discovery rule. Servers that already run a network devices discovery rule won't be listed.
Select Create Resource Pool to create a management server resource pool for monitoring the devices, or in the Select a resource pool dropdown list, select a resource pool, and select Next.
On the Discovery Method page, select Explicit discovery or Recursive discovery, and select Next.
Note
If you know all of the network devices that you want discovered, you should use explicit discovery. Recursive discovery can discover devices that you've no business need to monitor and as a result, can increase the administrative workload of monitoring your network.
On the Default Accounts page, if you're discovering only SNMP v3 devices, select Next. If you're discovering any SNMP v1 or v2 devices, do the following:
If you previously created Run As accounts for SNMP v1 or v2 devices, the Run As accounts will be listed and you can select a listed account for this discovery rule. If no accounts are listed or the listed accounts aren't appropriate for this discovery rule, continue to the next step.
Note
If you're creating a recursive discovery rule, you must create a default account, which will be used to connect to and discover devices connected to the device that you specify on the Devices page. If you don't create and select an account on the Default Accounts page, the recursive discovery will discover the device that you specify but won't discover devices connected to it.
Select Create Account.
In the Create Run As Account Wizard, on the Introduction page, select Next.
In the Display Name text box, enter a name such as Router Credentials.
Optionally, enter a description in the Description box. Select Next.
On the Credentials page, enter the SNMP community string for your network devices, and select Create.
Note
If the rule will discover devices that use more than one SNMP community string, you must create one Run As account for each SNMP community string.
On the Default Accounts page, you'll see that the Run As account that you just created is listed in the SNMPv1/v2 Run As accounts box and is selected. Select Next
If you're adding an SNMP v1 or v2 device, on the Devices page, do the following:
Note
This procedure describes how to add devices one at a time. You can also add multiple devices by selecting the Import button to import a text file with a list of IPv4 addresses. This file should have a single IP address on each line. After import, the IP addresses are part of the discovery rule and the text file is no longer needed.
Select Add to open the Add Device page.
On the Add Device page, enter the IPv4 address or FQDN of the device that you want to discover and monitor. If you're creating a recursive discovery, the discovery will access this device to locate other devices on your network.
In Access Mode, select ICMP, SNMP, or ICMP and SNMP. This specifies how the device will be discovered and how it will be monitored after discovery.
Note
If you select ICMP and SNMP, the device must be accessible by both protocols or it won't be discovered. If you select ICMP, discovery will be limited to the specified device, and monitoring will be limited to whether the device is online or offline.
In Port number, retain the default port (161) or select another port number for the device.
Select v1 or v2 from the SNMP version dropdown box.
In SNMP V1 or V2 Run As account, select Use selected default account. If you specify an account in this window, then only the specified account will be used for discovery.
Note
If you're discovering devices that use more than one SNMP community string and therefore have multiple Run As accounts, you can retain the default value of Use selected default accounts in the SNMP V1 or V2 Run As account field. When you do this, the Network Devices Discovery Wizard will attempt to use the community string for every Run As account that you selected on the Default Accounts page against every device that you add to the discovery list until a community string succeeds.
Select OK. This returns you to the Devices page, and you should see the device that you just added listed.
Note
The Advanced Discovery Settings button on the Devices page opens a dialog that contains a number of settings that you can use to configure discovery of network devices, such as number of retry attempts. If you know you're going to discover more than 1500 devices, you must change the Maximum number of devices to discover in Advanced Discovery Settings.
Add other SNMP v1 or v2 devices and Run As accounts as necessary, and select Next.
Note
If you add multiple devices to the rule, you can set a common Run As Account for all of them by selecting all of the devices and then selecting Edit.
If you're adding an SNMP v3 device, on the Devices page, do the following:
Note
This procedure describes how to add devices one at a time. You can also add multiple devices by selecting the Import button to import a text file with a list of IPv4 addresses. This file should have a single IP address on each line. After import, the IP addresses are part of the discovery rule and the text file is no longer needed. Each device requires an SNMP v3 credential. After you import the addresses, you can edit each device to add the credential or you can select multiple devices and provide the same credential for all selected devices.
Select Add. This opens the Add Device page.
On the Add a Device page, enter the IPv4 address or FQDN of the SNMP v3 device that you want to discovery and monitor.
In Access Mode, select ICMP, SNMP, or ICMP and SNMP. This specifies how the device will be discovered and how it will be monitored after discovery.
Note
If you select ICMP and SNMP, the device must be accessible by both protocols or it won't be discovered. If you select ICMP, discovery will be limited to the specified device, and monitoring will be limited to whether the device is online or offline.
In Port number, retain the default port (161) or select another port number for the device.
Select v3 from the SNMP version dropdown box.
Select Add SNMP V3 Run As Account.
Note
Each SNMP v3 device requires its own Run As account.
In the Create Run As Account Wizard, on the Introduction page, select Next.
Enter a value in the Display name box, optionally enter a description, and select Next.
On the Credentials page, enter the values for User name, Context, Authentication protocol, Authentication key, Privacy protocol, and Privacy key for the SNMP v3 device. Select Create.
Select OK. This returns you to the Devices page.
The Advanced Discovery Settings button on the Devices page opens a dialog that contains many settings that you can use to configure discovery of network devices, such as the number of retry attempts. If you know you're going to discover more than 1500 devices, you must change the Maximum number of devices to discover in Advanced Discovery Settings. For more information on the available settings, see How to configure network device discovery settings.
Add other SNMP v3 devices and Run As accounts as necessary, and select Next.
If you're creating an explicit discovery rule, go to the next step. If you're creating a recursive discovery rule, do the following:
On the Include Filters page, leave the default setting to discover all devices. If you want to filter for only a particular set of devices, select Discover only network devices within the specific IP address ranges, and select Add to configure a filter. Select Next when complete.
In the IP address range field, you can enter addresses such as the following:
10.193.220.25 (a single IP address to include one specific device)
172.23.136<1-100> (include any IP address from 1 to 100 in 172.23.136/255.255.255.0)
172.23.135.\* (include any IP address in 172.23.135/255.255.255.0)
Note
For more information on formatting an IP address range, see How to configure network device discovery settings.
On the Exclude Filters page, leave the default setting to not exclude any of the discovered devices. If you want to filter an IP address from being discovered, select Add and specify an IP address. Select Next when complete.
Note
Although the dialog states that an IP address or host name can be entered for an exclude filter, only an IP address is valid. A host name can't be specified here.
On the Schedule Discovery page, either accept the default value of Saturday at 2 AM or specify an alternate schedule, and select Next.
Note
We recommend that you don't run network discovery more frequently than twice per week because network discovery can take hours to complete and may place an excessive load on the management server or gateway server during discovery.
Review your settings on the Summary page, and select Finish when you're ready to proceed.
You'll see a Warning popup that reads "The following accounts need to be distributed to the health service management server name in order for the discovery to work: DiscoveryName\Run As Account. Would you like Operations Manager to distribute the accounts? Yes: Distribute the accounts and create the discovery. No: Do not distribute the accounts and do not create the discovery." Select Yes.
The wizard completes and you see the message The network discovery rule was successfully created. Ensure Run the network discovery rule after the wizard is closed is selected if you want the rule to run immediately, and select Close. The network devices discovery rule is created. If you didn't select Run the network discovery rule after the wizard is closed, the discovery rule will run on the scheduled day and time.
Note
It can take several minutes for the network discovery rule to appear in the Operations console and begin discovery if you select Run the network discovery rule after the wizard is closed.
To monitor the progress of network device discovery, watch the status column of the discovery rule. It will provide the following statuses while it's running, along with the number of devices that it has located:
Probing
During the probing phase, Operations Manager attempts to contact a device using the specified protocol, as follows:
ICMP only: ping the device
ICMP and SNMP: contact the device using both protocols
SNMP only: uses the SNMP GET message
Processing
After probing is complete, Operations Manager processes all of the components of the device, such as ports and interfaces, memory, processors, VLAN membership, and HSRP groups.
Post Processing
Operations Manager correlates network device ports to the servers that the ports are connected to, inserts items into the operational database, and associates Run As accounts.
To confirm the successful discovery and management of the devices, select Device Management, and then select Network Devices. You should see your discovered devices listed in the results pane.
If a network device discovery rule fails, the device or devices will be listed in Network Devices Pending Management. This can be a subset of the devices specified in the discovery rule. Use one of the following methods to retry the discovery:
To attempt to discover that specific device only, right-click the device in Network Devices Pending Management and select Submit rediscovery.
To retry a recursive discovery that begins with that device, select Discovery Rules, right-click the respective rule, and select Run.
To change the discovery type of a network devices discovery rule
In the Operations console, in the Administration workspace, select Discovery Rules.
In the results pane, right-click the discovery rule that you want to change and select Properties.
On the General Properties page, select Next.
On the Discovery Method page, select the type of discovery you want the rule to use.
Follow the instructions for creating a discovery rule to complete the remaining wizard pages, and select Save.
Next steps
To view information about the network devices you're monitoring, see Viewing Network Devices and Data in Operations Manager.
To understand how to configure what to monitor and alert with your network devices, see How to configure monitoring of network devices.
To understand how to stop monitoring a network device, see How to Delete or Restore a Network Device in Operations Manager.
Feedback
Coming soon: Throughout 2024 we will be phasing out GitHub Issues as the feedback mechanism for content and replacing it with a new feedback system. For more information see: https://aka.ms/ContentUserFeedback.
Submit and view feedback for