Sorry about not getting back sooner (returning from vacation) but the QNX network message passing ran over Ethernet, not IP, so it only worked (to my knowledge)

Sorry about not getting back sooner (returning from vacation) but the QNX network message passing ran over Ethernet, not IP, so it only worked (to my knowledge) over a local segment. Given that it was transparent to user processes, it could be argued that security could be added at that layer (two of the seven layer OSI model).