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Every discovery range you create must be associated with a network view. If no network views are specifically defined in your deployment, your discovery ranges will automatically be assigned to the automatically created network view Network 1. For the first discovery of the network, this network view is automatically assigned to the SCAN1 port when you set up the appliance using the configure server command.

If more than one network view exists, you can choose the network view with which the discovery range will be associated, by clicking the Network View drop-down menu. If only one network exists in NetMRI, this setting does not appear. The chosen network view must also be associated with a scan interface. Otherwise, discovery does not take place. Unassigned network views that do not have an assigned scan interface or virtual scan interface appear with theicon in discovery ranges configuration. For more details, see Configuring Network Views.

Network views can contain multiple discovery ranges. So when you create other ranges, you can assign the same network view to each. However, you can assign each discovery range to only one network view. Also, ensure that the ranges you assign to each network view make sense. Selecting the network view in an Operations Center environment also involves other details. For more information, see Defining Discovery Ranges on Operations Center Collectors.

You can define discovery ranges that will be excluded from management. This is useful for devices you may not want to manage, but want to know about for inventory purposes. End Host network segments are a good example.


For discovery ranges, configuring Discovery Blackouts requires the use of the Admin account.

To create a discovery range, complete the following:

  1. Obtain or calculate the network range values. You can define a Network address (expressed as CIDR: in effect, a subnet prefix), an IP range, or an IP pattern.
  2. Click the Settings icon > Setup > Discovery Settings > Ranges.
  3. Click New.
  4. Choose an appropriate way to specify the range: 
    • CIDR: Enter the IP Prefix value and its CIDR subnet value in the drop-down.
    • IP Range: Specify an IP range using a beginning and ending value.
    • IP Pattern: Specify a wildcard pattern for matching IP addresses.
  5. For Discovery Mode, select one of the following:
    • Include in Discovery: Any device found matching that range is discovered and managed by NetMRI.
      Discovery gives the highest precedence to devices found in an Include in Discovery range, ensuring they will be the first to appear in information tables in the appliance.
    • Exclude from Discovery: Instructs NetMRI to ignore the specified values and do not discover them through any of the specified protocols. Ranges set to an Exclude from Discovery setting are simply excluded, given the lowest precedence, and will not be discovered.
    • Exclude from Management: Indicates that NetMRI discovers any device found matching that range, but NetMRI will not manage or collect data from the device. Network devices found in an Exclude from Management range are given moderate precedence and will, over time, appear in information tables applicable to unmanaged devices. End host network segments are an example.


If you are discovering end-host subnetworks for Switch Port Management, choose the Exclude From Management option for the end host discovery ranges.


An advanced setting, Discovery Status Precedence (Settings icon > NetMRI Settings > Advanced Settings > Discovery group–> Discovery Status Precedence), governs the global setting for exclusion ranges. Changing this Advanced setting to Longest Prefix Match enables an exclusion range to contain smaller IP ranges that can be matched against to allow discovery — for example, you can exclude a /23 network, but Include a /24 prefix within the EXCLUDE range, because the /24 is a longer prefix.

5. To use a discovery ping sweep for discovery on IPv4  networks, check the Enable Discovery Ping Sweep check box. This implies a probe that uses a range of packet types to detect the presence of a system on each IP in the specified range, with ICMP Echo, ICMP Timestamp, TCP SYN to port 80, and TCP SYN to ports 161, 162, 22, and 23 (for the SNMP, SNMPTRAP, SSH, and TELNET services correspondingly). A ping sweep is not available for IPv6 network values. For more information on ping sweeps, see Defining Group Data Collection Settings.


The discovery ping sweep feature differs from the Smart Subnet ping sweep in the following ways: the discovery ping sweep will run only against the specified range, the sweep will run regardless of the range size, and the sweep will run regardless of the number of discovered devices within the specified range.

6. Select the Enable Discovery Blackout check box and click its Scheduling icon.

7. Define your schedule as follows:

    • In the Recurrence Pattern dropdown, choose how often you want to execute the blackout period. You can select OnceDailyWeekly, or Monthly.

    • If you choose Once:
      • Choose an Execution Time from the drop-down list.
      • Enter the date of the blackout in the Day_of_ field.
      • Specify the Duration: 10 or more Minutes, Hours, or Days.

    • If you choose Daily, click either Every Day or Every Weekday.
      • Choose an Execution Time from the drop-down list.
      • Specify the Duration: 10 or more Minutes, Hours, or Days.
    • If you choose Weekly, complete the following:
      • Choose an Execution Time from the drop-down list.
      • Check the check boxes for one or more days from Sunday through Saturday.
      • Specify the Duration: 10 or more Minutes, Hours, or Days.
    • If you choose Monthly, complete the following:
      • Choose an Execution Time from the drop-down list.
      • Day __ of every __ month(s): Specify for the discovery blackout to be executed on day-of-month X of every Y month. Month numbering starts with January. You can see some examples below.
        Day 5 of every 1 month(s): means the blackout is executed on the 5th of the current and each next month.
        Day 5 of every 2 month(s): means the blackout is executed on the 5th of January, March, May, July and so on. 
      • Specify the Duration: 10 or more Minutes, Hours, or Days.


For more information about discovery blackouts and change blackouts, see Defining Blackout Periods.

8. Select the Enable Change Blackout check box and click its Scheduling icon. Follow the instructions for the Enable Discovery Blackout setting in the previous step.

9. Click Add to place the new discovery range into the Range table.

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