The Manager primary contact has the option to automatically set the tracking method to DNS for hosts when a valid DNS hostname is detected. This applies only when scans are launched by DNS hostname.
1) The Manager primary contact can go to Scans > Setup > DNS Tracking.
2) Select the option "Enable DNS Tracking for hosts" and click Save.
With this option enabled, scan results for hosts with a valid DNS hostname will be tracked by DNS if the scan was launched by DNS hostname.
Note: There is another option to track all assets by DNS if valid hostnames are found. This option is available only for Admin. Once Admin enables it, all the assets will be tracked by DNS when valid hostname is detected irrespective of whether the scan is launched by DNS or IP.