Discovering Network Devices

Network Discovery helps administrators understand what devices are connected to their networks - their type, manufacturer, and other information - and when they join and leave the network. Configuring Network Discovery involves selecting one or more Clients to do the scan and the defining the range of IP addresses they should scan. Once configured, the scan begins immediately and remains active in the background. Scanned devices appear in the Assets tab.

To see Network Discovery in action, follow these steps:

  1. From the Asset Management menu, select Configure Network Scan. This opens the Network Scan Configuration dialog.

    net_scan_config.gif
     

  2. Press the Add button. This creates a new Scan Definition named "Network Scan", which typically corresponds to a subnet that you wish to scan. Rename this scan definition if so desired.

  3. In the Scan Agent drop-down list, select a Client to serve as the "Scan Agent". The Scan Agent is simply a client designated to run the scan. It is typically (although does not have to be) in the same subnet that it will scan.

  4. In the IP Addresses textbox, enter the range of IP addresses that this scan agent should scan. For example, 192.168.1.1 through 192.168.1.254:

    net_scan_config_2.gif

  5. Permissions may be required to run a network scan in your network. Network Discovery uses Windows APIs and SNMP to perform the scan. Hence, domain and/or SNMP credentials may be required for the Scan Agent to successfully perform the scan. Check with your network administrator to determine the accounts necessary to run the scan. If there are some, then:

    1. Press the Add/Delete Accounts button. This opens the Accounts dialog.

    2. Select the Domain or SNMP tab, and press Add to add credentials (account credentials for Domains, community strings for SNMP).

    3. Repeat (2) as required.

    4. Press the OK button.

    5. In the Account dropdown list, select any accounts necessary to perform the scan within the defined IP range. The dropdown list will show how many of each type of account are configured for this Scan Agent.

  6. Select the Schedule tab. On this tab, you define how often and how deeply the Scan Agent should rescan the network. Under Rescan, select continuously. For production, return this setting to its default setting of Hourly (or Daily).

    net_scan_config_3.gif

  7. Press OK. The Scan Agent will immediately begin scanning the IP range you specified, collecting information about the network devices.

  8. Now let's see the results of the scan. Start by selecting the Assets tab in the Console.

  9. In the tree view, select the Scanned node. All scanned devices will appear in the details pane as Scanned devices. The scan can take some time to scan all the devices in the range, so the list will grow gradually over time. Right-click on a column heading and select More Fields to see other fields to display, such as Model. The Asset Type column indicates the type of the Asset, if known. If it cannot be detected, the type is "Generic Asset". The Managed column indicates whether or not the device is a computer being managed in your Channel.

    net_scan_results.gif

  10. Now click the Un-reviewed Assets node. The details pane will show all Assets that you have not marked as "Reviewed". Select an Asset, right-click, and select Mark as Reviewed. The Asset will be automatically removed from the list. Typically you will mark Assets as "Reviewed" after you have examined and assessed the Asset and perhaps adjusted some of its properties. The Un-reviewed Assets node in the tree will display an exclamation point icon unreviewed.gif when there are Assets to be reviewed. This visual indicator provides a quick way to see if there are any new Assets that have been scanned on the network.

  11. There are other nodes in the tree that are automatically created and populated. The By Asset Type node organizes your Assets by their type.

    byType.gif

  12. Now select the By Manufacturer node. This node organizes your Assets by their manufacturer. The groups are created and populated automatically. The specific sub-nodes under the By Manufacturer node will depend on your specific devices. The manufacturer is specified by the MAC address of a scanned device. The mapping of MAC addresses to manufacturers is maintained by the IEEE standards organization.