Hello,
I have several routers in my home and my Omnia is the gateway to the internet. Port Forwarding from the Internet to a directly connected server works. And the same is true for client in Omnia’s subnet. But connections to the external IP of Omnia from other subnets behind routers directly connected to the Omnia are rejected.
Running tcpdump on Omnia proves that a connection request reaches the Omnia. But they are not forwarded. Looking at iptables shows that only rules from it’s own subnet (192.168.2.0/24) are created (NAT Loopback rules?). But other subnets are ignored.
And what is really amazing, there is another linux server for emails. And this server can connected (port 25, 587, 993).
And I don’t expect port 443 is handled specially.
Help is highly appreciated because my server infrastructure works only in my DMZ 
.
Best regards,
Martin