Cell Modem IP Address

I am using a external cellular modem to connect to the internet. How do I set up the modems IP address so that I can read the modem status via MODBUS? When I set the IP address the same as my LAN addresses, the Flexy cannot connect to the internet. When I have the IP set different than the LAN IP, everything works.

Is this a 3rd party modem or an Ewon extension card modem?

First, you can’t change the IP address of any cellular modem without first consulting with the cellular company. They determine the correct IP address to use.

Second, the Ewon is a router, so the LAN and WAN must be on different subnets. They can’t have the same IP address or both have IP addresses in the same subnet.

Please clarify what type of modem you are using so that we can help.

The modem that I am using is a Teltonika RUT240. This modem has Modbus and I would like to be able to read the signal strength. My Flexy LAN IP is and my modem’s IP address is

You’ll need to change the NAT and firewall settings in comcfg.txt to be able to reach the modem from the Ewon and the LAN. Go to ‘Setup > System > Storage > Edit COM cfg’ and change the following settings:


You will also need to make sure that any devices on the LAN network have their default gateway set to be the Ewon’s LAN IP (1992.168.150.100) now. Make sure to reboot the Ewon after making the changes.