After a device is added to the database, WhatsUp Gold begins watching that device using ICMP (Internet Control Message Protocol). WhatsUp Gold 'bounces' a message off of the device, then waits for the echo reply. If the reply is not returned, WhatsUp Gold considers it unresponsive device and changes the status color of the device.
By default, WhatsUp Gold uses the IP address of the device to send this message. You can change this to use the Host name or the Windows name of the computer, and you can change the means it uses to poll the devices.
To change how you poll a device:
This is useful if you want to monitor a device that has a dynamic IP address instead of an address assigned to that device. You will need to choose Poll using Host name so the DNS will be able to find the device on the network.