major.io words of wisdom from a systems engineer

Share a wireless connection via ethernet in GNOME 3.14

There are some situations where you want to do the opposite of creating a wireless hotspot and you want to share a wireless connection to an ethernet connection. For example, if you’re at a hotel that offers only WiFi internet access, you could share that connection to an ethernet switch and plug in more devices. Also, you could get online with your wireless connection and create a small NAT network to test a network device without mangling your home network.

Doing this in older versions of GNOME and NetworkManager was fairly easy. Newer versions can be a bit more challenging. To get started, I generally like to name my ethernet connections with something I can remember. In this example, I have a USB ethernet adapter that I want to use for sharing a wireless connection. Opening the Network panel in GNOME 3 gives me this:

Network control panel GNOME

Click the cog wheel at the bottom right and then choose the Identity tab on the next window. Use a name for the interface that is easy to remember. I chose Home USB Ethernet for mine:

Identity networkmanager panel

Press Apply and then go to a terminal. Type nm-connection-editor and you should get a window like this:

Network connectionc

We can add a shared network connection by pressing the Add button. Do the following afterwards:

  • Choose Ethernet from the list and press Create…
  • click IPv4 Settings
  • Choose Shared to other computers in the Method drop-down menu
  • Enter Share via ethernet as the Connection name at the top (or choose a name you prefer)

When that’s all done, you can close the Network Connections menu we opened via the terminal. Now open the Network control panel once more. It should have two profiles for your ethernet connection now (mine is a USB ethernet device):

Share via ethernet

If it’s not already selected, just click on the Share via ethernet text. NetworkManager will automatically configure NAT, DHCP and firewall rules for you. When you’re ready to go back to normal ethernet operation and you want to stop sharing, simply click on the other profile (mine is called Home USB Ethernet). NetworkManager will put the ethernet device back into the original way you had it configured (default is DHCP with automatic IPv6 via SLAAC).