OBS-URL: https://build.opensuse.org/package/show/security:netfilter/firewalld?expand=0&rev=81
iptables can co-exist but the 'nat' table had a bug which was fixed in kernel-4.18. OBS-URL: https://build.opensuse.org/package/show/security:netfilter/firewalld?expand=0&rev=78
OBS-URL: https://build.opensuse.org/package/show/security:netfilter/firewalld?expand=0&rev=77