I can't find any specifics on the required firewall ports for AAD Connect traffic (especially inbound). Table 2 in this article refers to this list of IPs, but it doesn't seem right that to allow AAD Connect communication one has to open all these IPs, which refer to Office 365 services anyway, so I am a bit lost
The arrow between AAD Connect server and AAD is bidirectional, so I assume traffic flows both way, unless the incoming only refers to the Health agent. Can it be that AAD Connect only needs outbound traffic and not inbound?
I have seen similar questions in other forums but things seem to have changed, or at least are still unclear to me