#71 MacIP LL assumes DDP socket 72 instead of using advertised socket
zero2sixd tracked down an error in the MacIP implementation of Marinetti. This statement from the MacIP IETF draft sums up what is happening:
The implementation SHOULD record the full AppleTalk address returned in the NBP response
(including the returned socket) and use it in subsequent transactions with the Server.
It SHOULD not simply assume that the Server is on DDP socket 72.
However, there are many existing implementations that make this assumption.
Marinetti makes this assumption. macipgw returns that it is listening on port 128 for DDP, but that is ignored by Marinetti and it sends the DDP (w/IP encapsulated) packets to port 72, which promptly drops them.
However...
It turns out that, while the client MacIP implementation should not assume 72, there are several places in the draft that say the gateway should listen on 72.