Hi Reco! Thanks for reply! I changed from /lib/systemd/system/networking.service.d/networking.service.conf to /etc/systemd/system/networking.service.d/networking.service.conf. > One can specify hostnames in netfilter rules. Trying to load such rules without a working resolver can lead to weird results. Yes, I thought about this. However, I use strictly IP addresses or prefixes in my firewall rules. Martin