opening doors - nat
The answer Sunshine provided may not be correct, and I will try to explain it as per my understanding.
As terziyski already responded, "The UPnP (Universal Plug and Play) protocol allows applications or host devices to automatically find the front-end NAT device and send a request to it to open the corresponding ports." Upnp handles port forwarding automatically and this is how UPnP works.
What's more, no more than one device can use a port at a time. If you need multiple devices to connect via a single External IP address then you must use a secondary port when referencing the second device from outside you’d have to use the alternate port. That's why UPnP changes the external port number automatically when it detects the corresponding port has been used by another device in the network.
Back to your issue, when UPnP changes the external port to 13547, the NAT type changes to Moderate, which should be also OK for playing the game (I assume?). Can you confirm?
1.on the first PC that starts the game it opens the ports with internal UPNP 3074 and external 3074. when I then start the second PC, without turning off the first, it opens the internal port 3074 but the external port does not open the right one.
instead of opening the 13547 it opens another one and I therefore nat moderated.
port 13547 is a variable port, it changes every time the game is started on the second PC.
2.if I manually enable the secondary port 13547 on the second PC the NAT becomes open to me. the problem is that every time you start the game on the second PC this secondary port changes
3.The game tells me which door I need to open in the connection properties
