
Schematic
I am trying to access MySQL DB from the MySQL DB client as shown in the above schematic.

The TRB140 is directly connected to the DB host using LAN and I can telnet to IP 192.168.2.212 on port 3306 from the TRB140(SSH session).

The TRB140 is connected to the OpenVPN server on the cloud and I can SSH into TRB140 from other clients like the MySQL DB client on the OpenVPN network.

Now, I want to access the DB from a MySQL DB client (participant of the OpenVPN network with the IP 10.8.0.2). This client can also SSH into TRB140 as shown above.

Firewall Settings on the TRB140

Port forward settings on TRB140
This doesn't work, I tried Traffic Rules and they seem to offer very similar settings as the port forwarding option but neither works alone or together.
Any help is highly appreciated.