It's probably ufw putting its rules in INPUT and OUTPUT chain and docker needing them in FORWARD. Don't blame ufw incompetence on iptables. There is separate

It's probably ufw putting its rules in INPUT and OUTPUT chain and docker needing them in FORWARD. Don't blame ufw incompetence on iptables. There is separate issue with bridging aptly described here https://wiki.libvirt.org/Net.bridge.bridge-nf-call_and_sysctl.conf.html https://wiki.libvirt.org/Net.bridge.bridge-nf-call_and_sysct... but IIRC docker doesn't work in that config by default. IIRC Centos/RHEL comes with bridging iptables pre-broken because they're bad at making firewall rules there.