Lets assume we have two local networks: 192.168.1.0/24 (Malasia) & 192.168.2.0/24 (Germany). And there is a VPN (10.10.10.0/24) server on host 192.168.2.1 with some public IP 18.104.22.168. Also we have a VPN client 192.168.1.5, so it has been assigned an IP: 10.10.10.2.
As I understand: every VPN client can ping any VPN resource/other_clients by its VPN IP (10.10.10.X) How does it works? For 192.168.1.0/24 we do not involve some dedicated public IPs. But we still can reach thous machines which under VPN. Does it some kind of NAT that allow web servers to respond to clients bihind the NAT? And do we need support from providers/routers to maintain the address translation for VPN traffic? VPN Passthrough?