I would like to find a tool that allows me to do the following:
I have machine A behind a NAT\Router with a web application, then I have server B accessible on the internet.
Using some application all TCP requesting incoming to server B on port N would be redirected to machine A on port 80. This way the web application would be exposed on the internet.
I would like to achieve this without changing any configuration on the router of machine A's network.
There would be some client tool running on machine A that would keep the connection open with server B and allow for this redirection.
In the future other machines like A, but on other local networks would have a similar mechanism where they would be reachable from the server B by usşing other ports.
Can anyone tell me what kind of tool I'm looking for? I keep reading about HTTP Tunnel and VPN, but I'm not sure that's exactly what I need.
Edit: Some missing information, A and B are running Windows, the NAT is usually done by a normal ADSL router, A and B are not on the same subnet nor behind the same NAT, A is behind the NAT, B is connected directly to internet.