
Problem:
I can ping a device on a cmd line just fine.
But this software shows it as "unknown". (I have to enable "show unknown" first, otherwise it does not even show the device.
I have deleted the cache and scanned the whole subnet again, but results are the same.
If it helps, some of these rogue devices are a APC UPS which is not responding to any SSH, telnet or HTTP, but it does respond to ping requests.