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Pratyush_Udhani7
Pratyush_Udhani7

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How to connect headless linux server to internet without network manager

#linux #homelab #devops #network

In a headless installation you can connect to wifi networks using network-manager, iwctl etc. But wait first you need to install these, and for that you need internet.

I was stuck in this egg-chicken problem myself and then I got to know about Netplan and wpa_supplicant.

In this guide, we'll walk through two methods to connect your Linux server to Wi-Fi using only built-in tools: Netplan and wpa_supplicant.

Method 1: Netplan

Netplan is Ubuntu’s default network configuration system. You can define Wi-Fi networks in a YAML file and let the system manage them.

Step 1: Edit Netplan configuration file

sudo vim /etc/netplan/01-netcfg.yaml
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The file name may vary. It will look something like this:

network:
  version: 2
  wifis:
    # wifi interface
    wlo1:
      dhcp4: true
      access-points:
        "SSID_1":
          auth:
            key-management: "psk"
            password: "password"
        "SSID_2":
          auth:
            key-management: "psk"
            password: "password2"
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Replace wlo1 with your own wifi interface. Use ip link show to find your interface.

Step 2: Apply the changes

sudo netplan apply
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This will:

  • Connect to the Wi-Fi
  • Request a DHCP IP address
  • Set up the default route

Step 3: Test your connection

ping google.com
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Method 2: wpa_supplicant

wpa_supplicant is the backend used by most Linux systems to handle WPA/WPA2 Wi-Fi authentication. It connects your Wi-Fi interface to a protected wireless network using a configuration file.

Step 1: Generate a Secure Wi-Fi Config

wpa_passphrase "YourSSID" "YourPassword" > wpa.conf
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This generated a config for your wifi. If you don't know the SSID, you can easily check it through some other device.

Step 2: Create the Configuration File

sudo vim /etc/wpa_supplicant/wpa_supplicant.conf
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Copy the contents of wpa.conf to this file.

Step 3: Start wpa_supplicant

sudo wpa_supplicant -B -i wlan0 -c /etc/wpa_supplicant/wpa_supplicant.conf
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Replace wlan0 with your own wifi interface. Use ip link show to find your interface.

Step 4: Test your connection

ping google.com
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Troubleshooting

  • Make sure the wifi interface is up by running sudo ip link set wlo1 down sudo ip link set wlo1 up.
  • wpa_supplicant might interfere by creating p2p-dev-wlan0 and I found it useful to kill it's instances to resolve those conflicts. sudo killall wpa_supplicant.

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