Depending on how settings are configured, you can enable and disable Firewall from the Trellix system tray icon.
Before you begin
Make sure that you have selected the Allow users to disable Firewall from the Trellix system tray icon option in the ePO - On-prem Firewall Option policy.
Task
Right-click the Trellix system tray icon and click Quick Settings → Disable Endpoint Security Firewall.
When Firewall is enabled, the option to Disable Endpoint Security Firewall is active and vice versa.
If you have selected the Require justification from users when managing Firewall from the Trellix system tray icon option in the ePO - On-prem Firewall Option policy, you are prompted to provide your administrator with a reason for disabling Firewall.