How to inventory hardware offline?

Question

Inventory

Hello! I couldn't find the answer in the search, I'm asking for help.
Introductory - a large distributed enterprise (distribution across different countries, data centers, etc.). There is a task to carry out inventory of all "iron".
What to do with computers within the network, in principle, is completely clear. The question is on the accounting of computers "remote workers". A large staff of users working remotely using company equipment (PCs, laptops). Most of these people never connect to the network. No VPN, no way. They do not use internal and other resources.
Is there some kind of accounting software with a client part, so that it would connect to the server on a schedule to force a report on the hardware component? Well, or in extreme cases, that would send a letter with data, even DxDiag.

Answer 1

I don't know if it's relevant or not.
But there is a program , it has clients who send information by mail and via FTP on a schedule. And what is convenient, it tracks changes after re-collecting information.