You have just deployed the first SES agent and you want turned it into a device discovery agent to find unknown devices in the network

​Note: You must have installed a SES Agent to enable device discovery. If you haven't installed any clients yet, please refer Creating a Symantec Agent installation package

1. Go to Settings > Device Discovery
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2. Select Select Discovery Agents.
   
3.  From the list of available clients, choose the Discovery agent and click done
   
   
   
4. You can choose if the system should be scan entire subnet or IP range within subnet by choosing select Edit IP Range under the scan range of the discovery agent,  You can also include public networks in discovery if needed. Once configured click done
   
5. Select Discover Now to begin Network Discovery in the selected IP network range
   
6. You can view the devices that the Device Discovery agent finds in Devices -> Unmanaged Devices

To push packages from the Symantec Endpoint Security (SES) console to discovered devices, please refer Push enrollment from the Symantec Endpoint Security (SES) console using Device Discovery