You run a Network Discovery and discover devices that you do not want to monitor.

The Discovery Ignore List is a feature that allows you to specify the IP addresses or hostnames of the devices that you do not want to monitor or discover in the future. You can add devices to the ignore list manually or automatically during the discovery process. Once a device is added to the ignore list, it will be skipped by any subsequent discovery. You can also remove devices from the ignore list if you change your mind and want to monitor them later. References: Add devices to the Discovery Ignore List in NPM, Remove devices from the Discovery Ignore List in NPM, How to View Devices on Your Windows Network and What to Do If You Can’t See Them