Can anyone recommend a scanning tool or method to find and inventory all and "missing" Mac OSX devices on the network? I am only concerned w/ macbooks and iMacs.
Apple Remote Desktop includes a network scanner that uses Bonjour or network ranges to add devices. It will detect macOS computers even if it doesn't have login credentials for them.
From known devices within the same subnet/VLAN you could run arp -a to find unknown devices, winnowing it down by looking for Apple assigned OUs (the first six characters of the MAC address), and then eliminating known devices.
If the Macs are bound to a directory server, compare a list of Apple objects on that server to known lists of Macs.
