How to make a VPN to access a local network with a gray IP?

Question

VPN

There is a router with a gray IP address, you need to configure a VPN to access local IPs from this router.
How to do it?

Answer 1

Hamachi

Answer 2

God, why don't people google before asking a question? There are only three ways
to build a VPN, there are no others! - Having a static white IP connect to the second party. This is how millions of tunnels work. - Having only a gray IP, connect to a previously known server, register there and wait for the server to contact the second party and establish a connection. Connection is possible not with anyone, but only with those who are also registered on the server. This is how all Hamachi servers and similar services work. Tunngle worked the same way. - Having only a gray IP, connect to your VPS that has a static white IP and connect to the VPS from it
Without a static white IP and without using intermediaries, it is IMPOSSIBLE to install a VPN from a gray IP

Answer 3

1. Get an external routable ip on the router interface
2. Use a third party with an external ip to build a tunnel through not. Tritely the cheapest VPS (attention to openvz restrictions, etc.)
3. Third-party services that implement point 2 for you.