# Pastebin 88wMFKWq
After the rejection of the above change to the compiled-in defaults by
the kernel, many Linux distros (including Fedora, RHEL, and CentOS)
made an attempt to solve this problem by adding lines to
/etc/sysctl.conf to modify the default settings compiled into the
bridge module:

  net.bridge.bridge-nf-call-ip6tables = 1
  net.bridge.bridge-nf-call-iptables = 1
  sysctl -p