Using WPA_Supplicant to Connect to WPA2 Wi-fi from Terminal on Ubuntu 16.04 Server

In this tutorial, we are going to learn how to connect to Wi-fi network from the command line on Ubuntu 16.04 server and desktop using wpa_supplicant.

In a modern home wireless network, communications are protected with WPA-PSK (pre-shared key) as opposed to WPA-Enterprise, which is designed for enterprise networks. WPA-PSK is also known as WPA-Personal. wpa_supplicant is an implementation of the WPA supplicant component. A supplicant in wireless LAN is a client software installed on end-user’s computer that needs to be authenticated in order to join a network.

Now let’s see how to connect to WPA2 wireless network using wpa_supplicant.

Step 1: Enable wireless interface

First, make sure your wireless card is enabled. You can use rfkill.

sudo apt install rfkill

To check the status of wireless card, run

rfkill list

Sample output:

ubuntu connect to wireless network command line

As you can see, my wireless card is blocked by software. To unblock it, use the following command:

rfkill unblock wifi

If you are using the desktop version of Ubuntu, then you also need to stop Network Manager with the following command, otherwise it will cause connection problem when using wpa_supplicant.

sudo systemctl stop NetworkManager

You also need to disable NeworkManager start at boot time by executing the following command.

sudo systemctl disable NetworkManager

Step 2: Find your wireless interface name and wireless network name

Run iwconfig to find the name of your wireless interface.

iwconfig

wlan0 is a common name, but my wireless interface is called wlp3s0. You can also see that it’s not associated with any access point right now.

connect to wifi terminal ubuntu

Then find your wireless network name by scanning nearby networks with the command below. Replace wlp3s0 with your own interface name. ESSID means network name.

sudo iwlist wlp3s0 scan | grep ESSID

ubuntu 16.04 connect to wifi command line

Step 3: Connect to Wi-fi network using wpa_supplicant

Now install wpa_supplicant on Ubuntu 16.04.

sudo apt install wpasupplicant

We need to create a file named wpa_supplicant.conf using the wpa_passphrase utility. wpa_supplicant.conf is the configuration file describing all networks that the user wants the computer to connect to. Run the following command to create this file. Replace ESSID and Wi-fi passphrase with your own.

wpa_passphrase your-ESSID your-passphrase | sudo tee /etc/wpa_supplicant.conf

wpa_supplicant ubuntu 16.04 wifi setup command line

The output will be piped to tee which then write to /etc/wpa_supplicant.conf file.

Now use the following command to connect your wireless card to wireless access point.

sudo wpa_supplicant -c /etc/wpa_supplicant.conf -i wlp3s0

By default, wpa_supplicant runs in the foreground. If the connection is completed, then open up another terminal window and run

iwconfig

You can see that the wireless interface is now associated with an access point.

how to enable wifi in ubuntu using terminal

You can press CTRL+C to stop the current wpa_supplicant process and run it in the background by adding -B option.

sudo wpa_supplicant -B -c /etc/wpa_supplicant.conf -i wlp3s0

Although we’re authenticated and connected to wireless network, but we don’t have an IP address yet. To obtain a private IP address from DHCP server, use the following command:

sudo dhclient wlp3s0

Now your wireless interface has a private IP address, which can be shown with:

ifconfig wlp3s0

connect to wifi terminal ubuntu 16.04

Now you can access the Internet. To release the private IP address, run

sudo dhclient wlp3s0 -r

Connecting to Hidden Wireless Network

If your wireless doesn’t broadcast SSID, then you need to add the following line in /etc/wpa_supplicant.conf file.

scan_ssid=1

Like below:

network={
        ssid="LinuxBabe.Com office network"
        #psk="12345qwert"
        psk=68add4c5fee7dc3d0dac810f89b805d6d147c01e281f07f475a3e0195
        scan_ssid=1
}

Auto Connect on Startup

To automatically connect to wireless network at boot time, we need to edit the wpa_supplicant.service file. It’s a good idea to copy the file from /lib/systemd/system/ directory to /etc/systemd/system/ directory, then edit it because we don’t want newer version of wpasupplicant to override our modifications.

sudo cp /lib/systemd/system/wpa_supplicant.service /etc/systemd/system/wpa_supplicant.service

sudo nano /etc/systemd/system/wpa_supplicant.service

Find the following line.

ExecStart=/sbin/wpa_supplicant -u -s -O /run/wpa_supplicant

Change it to the following. Obviously you need to change wlp3s0 if that isn’t your interface name.

ExecStart=/sbin/wpa_supplicant -u -s -c /etc/wpa_supplicant.conf -i wlp3s0

Save and close the file. Then enable wpa_supplicant service to start at boot time.

sudo systemctl enable wpa_supplicant.service

We also need to start dhclient at boot time to obtain a private IP address from DHCP server. This can be achieved by creating a systemd service unit for dhclient.

sudo nano /etc/systemd/system/dhclient.service

Put the following text into the file.

[Unit]
Description= DHCP Client
Before=network.target

[Service]
Type=simple
ExecStart=/sbin/dhclient wlp3s0

[Install]
WantedBy=multi-user.target

Save and close the file. Then enable this service.

sudo systemctl enable dhclient.service

That’s it!

I hope this tutorial helped you set up Ubuntu server 16.04 wifi from the command line. As always, if you found this post useful, then subscribe to our free newsletter. You can also follow us on Google+Twitter or like our Facebook page.

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7 Responses to “Using WPA_Supplicant to Connect to WPA2 Wi-fi from Terminal on Ubuntu 16.04 Server

  • user1397
    6 months ago

    You got me through a tough situation, thank you good sir!

  • This is such a detailed tutorial. Thanks very much!
    I’m curious about having an additional wifi adapter via USB and have it setup as an AP which bridges the connection to wlan0 which is connected to the internet.
    Does Ubuntu support bridging e.g. wlan0 and wlan1?
    I’ve been trying to get this to work on Xenial server but to not avail.
    Thanks in advance

  • Worked like a charm!!! Even giving me chills at the very beginning when you asks for someone seeking for internet connection to apt-get something (dam!) didn’t gave it up and jumped to Step 2! It took a while to understand the steps but finally I got it working.
    Would like to add that you need to initialize wireless interface once on Step 2 using:
    $ sudo ip link set wls3s0 up
    I’m bringing back to life an old Atom Acer netbook with Ubuntu server 16.04 (32bits) and was just mad why daheck have it discovered my wireless hardware beautifully on install process (I did insert SSID, passphrase, etc) and after first boot it was just gone!!!

    Well, I own you a few hours. So, thx =D

  • Doesn’t work on Ubuntu 18.04

  • Lyon Qiu
    6 months ago

    Great article! Works like a charm! Thank you!

  • Thank you very much for the detailed tutorial. I am sorry that it did not seem to work for me. After rebooting, there is still no connection. Where might the issues be? Thanks again 🙂

  • Nice guide for the most part, Steps 1 thru 3 working good and I can connect to Wi-Fi, but Auto Connect on Startup is not working. I checked journalctl and wpa_supplicant is spamming a whole bunch of “no such device” errors in there, but when I up-arrow thru my command history line by line and manually restart the supplicant it works fine. Will check out some other guides and post back here if I figure it out, thanks

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