VCID(Vendor Class Identifier) is a DHCP options, which send by clients to a server.[1][2] The imRAD can detect the enterprise id from this identifier. ↑ https://tools.ietf.org/html/rfc3925 ↑ https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms-dhcpe/62eae564-3480-496f-8925-3d06c12f4e49