Reverse no ip service, any solution?

Question

Domain Name System

There is a remote point, there is a router with a whistle, aipi is white-dynamic (+ no-ip.com is configured), is there any service \ way to make traffic in the opposite direction from one ip, the same noip service only in the other direction ... the meaning of the manipulation is to register on the central server in iptables. no-ip - solves the problem that I can knock on the router via xxxxx.ddns.net from anywhere, but how can I make the router knock from one xxxxx.ddns.net (conditionally)?

Answer 1

Apparently, your task is perfectly solved with the help of VPN. Gather all the machines into one virtual network and inside it already manage access as your heart desires.
If you need a specific server for all external (with respect to VPN) machines to have a given IP, give the VPN server an additional white static IP and teach the VPN server to send all traffic from this server to the external network from this additional IP. Similarly, all incoming traffic to this IP can be sent entirely to the source server.

Answer 2

PTR record in the domain will help.

Answer 3

vpn from a router where a thread in the world?
It's not clear what you want to achieve...