How to configure wpa_supplicant in Ubuntu server 20.04

For esoteric reasons I have a server which only has WiFi access to the network.

By copying the necessary dpkg files on a removable drive I've managed to install wpa_supplicant.

The thing that's bugging me is that on other distributions configuring it can be done by editing /etc/wpa_supplicant/wpa_supplicant.conf. But this doesn't work on Ubuntu because the systemd service file starts up wpa_supplicant without specifying a configuration file. There is no -c specified in its arguments.

Even the Ubuntu man page says the most common way to start it is by specifying a config file...

In most common cases, wpa_supplicant is started with:

 wpa_supplicant -B -c/etc/wpa_supplicant.conf -iwlan0

Because this is a server there is no GUI installed and I'm not using network manager (AFAIK)

I have of course confirmed that shutting down the systemd service and manually starting the Daemon from the command line will work. And I can of course modify the .service file. But this feels like the wrong solution.

Can anyone tell me how I am supposed to configure wpa_supplicant on Ubuntu server?

1 Answer

It is not necessary to manually configure wpa_supplicant.

Networking in recent Ubuntu server versions is managed by netplan. Check to see the name of your netplan file:

ls /etc/netplan

I will assume that the name of the file you found is 01-netcfg.yaml. Substitute your details here if not 01-netcfg.yaml.

We will amend the file to specify your details:

sudo nano /etc/netplan/01-netcfg.yaml

Change the file to read:

network: version: 2 renderer: networkd wifis: wlx-----: dhcp4: yes dhcp6: yes access-points: "network_ssid_name": password: "**********"

Please substitute your wireless interface name here instead of wlx----. Please note that the access point name and password are enclosed in quotation marks ". Spacing, indentation, etc. are crucial, please proofread carefully twice.

Save (Ctrl+o followed by Enter) and exit (Ctrl+x) the text editor nano. Follow with:

sudo netplan generate
sudo netplan apply

If you instead prefer a static IP address for the server, you can find the template here:

cat /usr/share/doc/netplan/examples/wireless.yaml