if I have a local ipv4 address can I use it from outside a network to talk across a NAT

Question

I have an application where I want a device inside a network behind a NAT to make a call to the public network giving a server its local address, Later, say 10 or 20 minutes later, I'd like the server to be able to contact the device inside the network.

Is there any protocol generally supported by firewalls/routers etc. that would direct me to the local node if I provided its actual current local address?

Thanks

Answer 1

No, there is no such protocol. Moreover, in the case of multiple NAT, the local node can only know its address behind the innermost NAT, and the server can only know the public address outside the outermost NAT, so you have no means of mapping through multiple NATs, or even knowing how many exist in the path.

The local node will have to initiate and maintain an open connection with the server if it wants to receive anything from the server.