Notes On Setting up WiFi Network Access on the WF2023 Ubuntu 22.04 Image

Credit for the original source for this article goes to John Buck, ICPC North America Greater New York Region

1. Overview

WiFi support is turned off by default in the ICPC World Finals OS image ("WF OS"), since WiFi usage is not allowed at the World Finals. In order to use WiFi on a local installation of the WF OS, two things are necessary: the OS image must contain a driver for the particular WiFi adapter you want to connect to, and the driver must be enabled.

Most WiFi adapters are supported by Ubuntu 22.04 and the WF OS has those drivers installed. In addition, the WF OS supports wpa_supplicant, a program providing support for WPA, WPA2 and WPA3 WiFi connectivity. wpa_supplicant is installed and running by default.

2. Identifying Your Wireless Adapter

The first step in enabling WiFi on your WF OS is to make sure that the system can see your WiFi adapter. To do this, enter the following command as the root user (or using sudo):

    iwconfig

This should produce output similar to the following:

    lo        no wireless extensions.

    eno1      no wireless extensions.

    wlp0s20f3  IEEE 802.11  ESSID:off/any
              Mode:Managed  Access Point: Not-Associated   Tx-Power=0 dBm
              Retry short limit:7   RTS thr:off   Fragment thr:off
              Encryption key:XXXX-XXXX-XXXX-XXXX-XXXX-XXXX-XX
              Power Management:on

The name of the device you are looking for should start with "wl", for example as in wlp0s20f3 above. If there is no "wl..." type device listed, it's likely that there are no drivers installed for your WiFi device. You may need to do research to find them.

3. Enabling Your Wireless Adapter

Assuming the system reports the existence of a WiFi device adapter, the next step is to enable that device. To do this, you will need to update the file /etc/network/interfaces.d/wl... (where the last component is the wl... name for your Wifi adapter). Specifically, you must add two things to this file: your WiFi adapter's "SSID", and something called the Pre-Shared Key (PSK). (The PSK is also sometimes called the WPAKEY, and these terms are used interchangably below.)

It is presumed that you know your adapater's SSID, and that you know the password for connecting to your adapter. You can use these two values, along with the Linux wpa_passphrase utility, to generate the required PSK. To do this, enter the command

    wpa_passphrase SSID wifiPassword

    wpa_passphrase ICPC2023 WF2023Sharm

    network={
       ssid="ICPC2023"
       #psk="WF2023Sharm"
       psk=ca967f5e0786f72dd1d284d28aae000b7a0680bd6a3c20841814b21a36525f39
    }

Once you have your SSID and PSK, as root or using sudo, edit the file /etc/network/interfaces.d/wl... (where again the last component is the name of your adapter). Note: the file must already exist or this probably won't work.

Initially, the contents of your wl... file will probably look something like this:

    allow-hotplug wlp0s20f3
    iface wlp0s20f3 inet dhcp

You need to add lines like the following to the file, replacing the <SSID> and <WPAKEY> fields with the appropriate values:

    wpa-ssid <SSID>
    wpa-psk <WPAKEY>

    allow-hotplug wlp0s20f3
    iface wlp0s20f3 inet dhcp
    wpa-ssid ICPC2023
    wpa-psk ca967f5e0786f72dd1d284d28aae000b7a0680bd6a3c20841814b21a36525f39

Once you have saved the updated file, restart the adapter using the following commands:

    sudo ifdown wl...
    sudo ifup wl...

At this point it should connect to your wireless network. If not, try rebooting. You can also check /var/log/syslog if you can't connect for some reason; often, there is interesting stuff in there.

4. Additional Notes:

• There are apparently issues connecting to WEP networks, so don't use them.
• You can change "allow-hotplug" to "auto" if you want in the above examples. This will force the system to wait for the WiFi to be connected before proceeding. However, this can cause the system to hang for a LOOOOOONG time during boot-up if the WiFi is not available -- so not necessarily a good idea....