I have two ZS boxes. Box A is behind a router with NAT. Box B has just one Public IP and is not behind NAT. I have VPN Client connections going from Box A to the server Box B no problems. But if I create a VPN connection with Box B as the client connecting to Box A as the server it won’t establish a connection.
Box A has WAN ETH00 192.168.10.2 and connects to router LAN with 192.168.10.1 address.
In the router I have forwarded the port I’m using with this VPN connection from the router to the 192.168.10.2 address of the ZS box but still it won’t establish a connection.
If I put the router in bridge mode and have ZS do the ppp authentication then the VPN connection is established. However, the ppp function in my ZS Box A seems to be broken now (not sure how but it doesn’t work at all anymore) so I need the router to do the ppp for now.