Upon inception, DCOM (Distributed Component Object Model) faced two major challenges:
program-based processing of information, which led to information being represented differently
backwards compatibility to existing COM and DDE applications
OLE is based directly on DCOM. The DCOM interface allows COM applications to be distributed on several computers, providing a single security concept.
DCOM applications are restricted by not:
running over firewalls
being platform independent (only Microsoft operating systems are supported)