Not all Debian systems have a GUI, and even though using WiFi on a server isn't common, there are plenty of instances where you're using WiFi with a headless setup, like on a Raspberry Pi. It's not difficult to connect using only the tools provided out of the box in Debian.

In this tutorial you will learn:
  • How to Scan for a Network
  • How to Generate a WPA_Supplicant Config
  • How to Set up a WPA_Supplicant Config File
  • How to Connect to Your WiFi
WPA Supplicant Configuration on Debian 10
WPA Supplicant Configuration on Debian 10.

Software Requirements and Conventions Used

Software Requirements and Linux Command Line Conventions
Category Requirements, Conventions or Software Version Used
System Debian 10 Buster
Software WPA_Supplicant
Other Privileged access to your Linux system as root or via the sudo command.
Conventions # - requires given linux commands to be executed with root privileges either directly as a root user or by use of sudo command
$ - requires given linux commands to be executed as a regular non-privileged user

Scan for a Network

Before you can connect to your network, you need to find exactly what you're connecting to. If you already know the name of the WiFi network that you want to connect to, this section isn't necessary, but if you're trying to connect without knowing the SSID off hand, this will help you find it.

First, find the name of your WiFi interface. Run the following, and write down the wireless interface. From here on, this guide will call it wlan0, but yours will probably be different.

$ ip a

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Next, you can scan the networks in the area to find the SSID you want to connect to. As root or with sudo, run:

$ sudo iwlist wlan0 scan | grep -i ssid
List WiFi Networks on Debian 10
List WiFi Networks on Debian 10.

Find the name of the network you want to connect to, and write it down.

Generate a WPA_Supplicant Config

WPA_Supplicant can generate its own configuration, or the beginnings of one, including encrypting your network passowrd, so it's not stored in plain text.

$ sudo wpa_passphrase networkname password > /etc/wpa_supplicant/wpa_supplicant.conf

Set up a WPA_Supplicant Config File

Now, use your favorite text editor to open /etc/wpa_supplicant/wpa_supplicant.conf.

Generated WPA Supplicant Configuration on Debian 10
Generated WPA Supplicant Configuration on Debian 10.

Take a look at the network block that was generated. It contains your network's name and both the plain text password and the encrypted one. The plain text is just there to show you what you entered, and it's commented out. Delete that line.



Above the network block, place the following line. It will allow users in the wheel group to manage WPA_Supplicant.

ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=wheel

Turn your attention back inside the network block now. If you're connecting to a hidden network, add the line below after your password.

scan_ssid=1

Then, add in the protocol and key management settings for WPA2. If you're using anything else, stop and upgrade to WPA2.

proto=RSN
key_mgmt=WPA-PSK

Next, tell WPA_Supplicant to use CCMP instead of TKIP. Again, if you're using TKIP, stop. It's proven itself not to be secure.

group=CCMP
pairwise=CCMP

The last thing you should include is the priority. If you're managing multiple networks here, give the highest priority value to the ones you want to connect to first.

priority=10

Save your configuration, and exit.



Connect to Your WiFi

In order to connect, you're going to need to restart WPA_Supplicant. It's a service, so you can restart it with systemctl.

$ sudo systemctl restart wpa_supplicant

Give it a few seconds to connect, and check that you're connected by running ip a again. You should see a local IP next to your wireless interface this time.

Conclusion

Because you set up your connection manually with a configuration, this should continue working until you change something yourself. You can easily connect to multiple networks, and keep them organize with this method too.

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