How to connect two clients behind NAT?

Question

VPN

Prompt the simplest decision to connect on TCP/IP two computers for NAT.
It is clear that you can use a VPN, but in this case, additional gestures are needed to install and configure connections.
I like how it works, for example, in TeamViewer (I entered the client ID and connected). But what is needed is not remote control, but the ability to forward other software.
Those. the ideal option is as follows:
- launched the utility on one client, it showed the ID
- launched the utility on another client, drove in the ID - connected
- registered a proxy in the application software or some special addresses as client-server addresses.

Answer 1

www.softether.org

Answer 2

Body movements in any scenario will be needed.
The easiest way cannot be recommended, because you did not describe neither the problem to be solved, nor the network diagram.
In the general case, if encryption is not needed, the easiest way would be to forward a port on the router to the desired machine, which is located on the natom. And with client to cling to it.