Rebooted back to 5.8.0-3-amd64, it works! Something happened with Linux 5.9...
- Bug#973990: shorewall: Fails to start with "Couldn't lo... Vincas Dargis
- Bug#973990: shorewall: Fails to start with "Couldn... Vincas Dargis
- Bug#973990: shorewall: Fails to start with "Co... Vincas Dargis