RUT241 Modbus/TCP through OpenVPN (Port forwarding)

Hi all, I’m struggeling to access a modbus tcp interface from outside through openvpn and hope somebody can help. This is the situation:

  • RUT241 connected to Internet over WAN port
  • Router works as openvpn client and says that the connection is online
  • Modbus Device is connected to LAN of the RUT241
  • Modbus connection has been tested. Device is sending modbus data. Device has static IP Address in range of the LAN IP adresses of the RUT241
  • Created a port forwarding like this:


Instead of WAN I selected openvpn as source zone, like described in another instruction.


The server is not getting any response on modbus requests through openvpn.

It seems the VPN connection is stable

What’s not clear to me, why I don’t see a remote IP Address of the Server? Is this correct?

This is my exact port forwarding configuration

It would also be ok to just route the entire traffic of openvpn to this one device. The vpn connection is just for this single device.
Can somebody help?


The rule appears to be correct. Could you please check if you have default gateway configured on your Modbus device and it’s pointing towards RUT241?

Please, try enabling Masquerading on the LAN (LAN => OpenVPN/WAN) zone. This way, the traffic should appear as coming from RUT241.

Let me know how it goes.

Kind Regards,

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