My direct connect capable trainer / the Zwift Companion app is not detected

Run the Zwift container with host networking

By default the Zwift container uses a bridge network that isolates it from the network the host system is connected to. This could make it impossible for the Zwift container to detect devices on the network such as a direct connect enabled trainer or the Zwift Companion app.

Allow the Zwift container to access the host network by setting the NETWORKING configuration option:

NETWORKING="host"

Check your firewall configuration

If you have issues with device detection over Wi-Fi or ethernet, they may be related to your system’s firewall. Some Linux distributions use firewalld instead of ufw, which is more restrictive and blocks multicast traffic by default, which is essential for discovering devices over Wi-Fi.

Distributions that use firewalld by default include:

  • CentOS 7 and newer
  • Fedora 18 and newer
  • openSUSE 15 and newer (including Tumbleweed)

To check if the firewall is the issue, you can temporarily disable firewalld:

systemctl stop firewalld

If your Wi-Fi trainer / Zwift Companion app is now detected, the firewall is indeed the culprit. Once you’ve identified this as the issue, you should configure your firewall to allow multicast traffic on your network instead of disabling it entirely:

  1. Identify your Wi-Fi / network name.

  2. Assign that network to a specific zone (e.g. home):

    (Assuming your distribution uses NetworkManager, which almost all do)

    Via GUI: On Plasma Settings (or similar), navigate to Wi-Fi → [network name] → General → Firewall Zone, and select home

    Via CLI:

    nmcli connection modify "<network name>" connection.zone home

  3. Allow multicast traffic on the zone:

    The zone home might already be pre-configured with multicast support. If not, manually allow multicast with:

    firewall-cmd --permanent --zone=home --add-rich-rule='rule family="ipv4" destination address="224.0.0.0/4" protocol value="udp" accept'

  4. Restart firewalld or reload the configuration for the changes to take effect (shouldn’t be needed but just in case):

    Reload configuration (recommended, no service interruption):

    firewall-cmd --reload

    Restart the service:

    systemctl restart firewalld