This is basically the problem here but reversed. I have a remote OpenVPN client which connects to my server and registers itself with the address 10.1.0.29. This address is easily accessible from the server, whether through ping, ssh, or the apache web server. However, other machines on the local network of the server cannot access this 10.1.0.29 address in any way.
What could be the issue? The OpenVPN server does have ip_forwarding turned on, and the system works fine when the OpenVPN client is on the same LAN as the OpenVPN server. But as soon as the OpenVPN client is on a remote connection, it is not accessible to any machines on the ovpn server's LAN, only to the server itself.
See photo below: the packet is arriving to server and then even being retransmitted:
UPDATE: The client is receiving the packet too, it just refuses to acknowledge or do anything with it.