OpenVPN client blocking out out of band incoming traffic

Hello I connected a few of our Digi TransPort WR11 to our OpenVPN server and it worked great.

but I want the modem to block out of band incoming and outgoing traffic when it’s connected to our OpenVPN server. Most cellphone modem have that option in the WebUI but I can’t find how to do it on the Digi WR11.

Basically once it is connected to the OpenVPN server I want the modem to not accept communication that comes outside of the VPN or outside of the LAN.

Right now I can still access the modem and everything connected to it via it’s public IP address provided by the cellphone provider.

I have Moxa and Sierra modems that are able to do that without any issue but i’m having a hard time with the Digi modem to figure how to do it.

Thank you

Hi! I encountered a similar problem with my Digi modem connection. If anyone knows of anything that can be done to get rid of this problem, please help! thanks in advance