And again, an interesting question about traffic tunneling.

Dear friends, do you know how to make available on the Internet the necessary port of a computer connected to the Internet via NAT (need windows solution)?

I see myself solving the problem in this form:
1) On any server on the Internet we install special software that opens a port available on the Internet.
2) The computer hidden behind the NAT connects itself to our server and leaves the connection open.
3) Traffic is tunneled over this connection.

The option of picking in the NAT router (forwarding the port of the router-port on the network), please do not offer.