Fallback

Supported on: Firefox 124 or later, Firefox 115.9 ESR or later

Registry

HKLM Software\Policies\Mozilla\Firefox\DNSOverHTTPS

HKCU Software\Policies\Mozilla\Firefox\DNSOverHTTPS

Value name: Fallback

Enabled: Fallback = 1

Disabled: Fallback = 0

Description

If this policy is disabled, Firefox will not fallback to your default DNS resolver if there is a problem with the secure DNS provider. If this policy is enabled or not configured, Firefox will use your default DNS resolver if there is a problem with the secure DNS provider.