.. _gateway-m-cellular:

Share Cellular Connection via Ethernet
=======================================

This guide explains how to share a cellular connection via Ethernet on the
**Edge IoT Gateway M**.

Configure NetworkManager Firewall Backend
-----------------------------------------

Configure NetworkManager to use ``iptables`` as the firewall backend:

.. code-block:: bash

   sudo install -d /etc/NetworkManager/conf.d
   sudo tee /etc/NetworkManager/conf.d/99-firewall-backend.conf > /dev/null <<'EOF'
   [main]
   firewall-backend=iptables
   EOF

Reboot the Gateway
------------------

Reboot the Gateway to apply the changes:

.. code-block:: bash

   sudo reboot

Identify the Ethernet Interface
-------------------------------

Edge IoT Gateway M has two Ethernet interfaces. Check which interface is
connected to the device that should receive the shared Internet connection:

.. code-block:: bash

   nmcli device status

The Ethernet interfaces are typically listed as ``eth0`` and ``eth1``.

The examples below use ``eth0``. If you want to use ``eth1``, replace
``eth0`` with ``eth1`` in the commands below.

Configure Cellular and Ethernet Connections
-------------------------------------------

.. important::

   If you are connected to the Gateway over Ethernet, run all four commands
   below together. Enabling the shared Ethernet connection may interrupt your
   current connection to the Gateway.

Run the following commands:

.. code-block:: bash

   sudo nmcli connection add type gsm ifname cdc-wdm0 con-name cellular apn internet
   sudo nmcli connection up cellular
   sudo nmcli connection add type ethernet ifname eth0 con-name shared ipv4.method shared ipv4.addresses 10.42.0.1/24
   sudo nmcli connection up shared

Verify the Configuration
------------------------

Check active NetworkManager connections:

.. code-block:: bash

   nmcli connection show --active

Both the cellular and shared Ethernet connections should be active.

Check the IP address assigned to the Ethernet interface:

.. code-block:: bash

   ip addr show eth0

The interface should use the following address:

.. code-block:: text

   10.42.0.1/24

Connect another device to the selected Ethernet port. The connected device
should automatically receive an IP address from the ``10.42.0.0/24`` network
and use the Gateway's cellular connection to access the Internet.