Configure WiFi Connections in Ubuntu Using nmcli

Ubuntu is a versatile open-source operating system that powers desktops, servers, and IoT devices. Managing WiFi connections via the command line can be a powerful skill, especially when dealing with servers or minimal installations without a graphical interface. This guide will walk you through establishing and managing WiFi connections using nmcli, Ubuntu’s command-line tool for NetworkManager.

Prerequisites

• Ubuntu Operating System: Ensure you are running Ubuntu on your machine.
• Terminal Access: You should be comfortable opening and using the terminal.
• Administrative Privileges: Some commands may require sudo to execute.

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Step 1: Identify Your WiFi Interface

First, you need to find out the name of your WiFi interface. This is essential for executing commands that interact with your WiFi hardware.

nmcli d

Sample Output:

DEVICE      TYPE      STATE         CONNECTION
eth0        ethernet  connected     Wired connection 1
wlan0       wifi      disconnected  --
lo          loopback  unmanaged     --

In this example, wlan0 is the WiFi interface. Your interface might have a different name like wlp2s0 or similar.

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Step 2: Ensure WiFi Radio is Turned On

Before attempting to connect to a network, make sure that the WiFi radio is enabled.

nmcli r wifi on

This command turns on the WiFi radio if it was off. You can verify the status by running nmcli r.

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Step 3: Scan for Available WiFi Networks

Now, let’s scan for available WiFi networks to connect to.

nmcli d wifi list

Sample Output:

*  SSID            MODE   CHAN  RATE        SIGNAL  BARS  SECURITY
   HomeNetwork     Infra  6     54 Mbit/s   75      ▂▄▆_  WPA2
   OfficeWiFi      Infra  11    130 Mbit/s  60      ▂▄__  WPA2
   CoffeeShop      Infra  1     195 Mbit/s  45      ▂▄__  --

Identify the SSID (network name) you wish to connect to.

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Step 4: Connect to a WiFi Network

To connect to a WiFi network, use the following command, replacing <SSID> with the network name and <password> with the WiFi password.

nmcli d wifi connect <SSID> password <password>

Example:

nmcli d wifi connect HomeNetwork password MySecretPassword

• <SSID>: The name of the WiFi network.
• <password>: The WiFi password (must be between 8-63 characters or 64 hexadecimal characters for a 256-bit key).

Upon successful connection, nmcli will create a connection profile that you can see with nmcli c.

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Connecting to a Hidden Network

Hidden networks do not broadcast their SSID, so they won’t appear in the list of available networks. To connect to a hidden network, you need to create a connection profile manually.

Step 1: Add a New WiFi Connection

nmcli c add type wifi ifname <interface> con-name <connection_name> ssid <SSID>

Example:

nmcli c add type wifi ifname wlan0 con-name HiddenNetwork ssid MyHiddenSSID

• <interface>: Your WiFi interface name (e.g., wlan0).
• <connection_name>: A name you choose for this connection profile.
• <SSID>: The SSID of the hidden network.

Step 2: Configure Security Settings

If the hidden network is secured (which is usually the case), you need to specify the security type and password.

nmcli c modify <connection_name> wifi-sec.key-mgmt wpa-psk wifi-sec.psk <password>

Example:

nmcli c modify HiddenNetwork wifi-sec.key-mgmt wpa-psk wifi-sec.psk MyHiddenPassword

• <connection_name>: The name of the connection profile you created.
• <password>: The WiFi password.

Step 3: Bring Up the Connection

Finally, activate the connection.

nmcli c up <connection_name>

Example:

nmcli c up HiddenNetwork

If everything is configured correctly, you should now be connected to the hidden network.

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Managing WiFi Connections

Listing All Connection Profiles

To view all saved connection profiles, use:

nmcli c

Deleting a Connection Profile

To delete a connection profile you no longer need:

nmcli c delete <connection_name>

Example:

nmcli c delete HiddenNetwork

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Tips and Troubleshooting

• Incorrect Password: If you enter the wrong password, the connection will fail. Re-run the nmcli c modify command with the correct password.
• Interface Down: If your WiFi interface is down, bring it up with sudo ifconfig <interface> up or ensure that the WiFi radio is on using nmcli r wifi on.
• No WiFi Adapter Found: Ensure your device has a WiFi adapter and that it’s properly installed and recognized by the system.

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Further Information

For more advanced configurations and options, refer to the official nmcli documentation:

• NetworkManager Reference Manual - nmcli

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— By mastering nmcli, you gain powerful control over network connections directly from the terminal, which is especially useful for server management, scripting, or recovering network connectivity when the GUI is unavailable.