[CentOS] firewalld / iptables / nftables

Tue Jun 9 14:30:27 UTC 2020
Leon Fauster <leonfauster at googlemail.com>

Am 09.06.20 um 15:27 schrieb Chris Adams:
> Once upon a time, Jonathan Billings <billings at negate.org> said:
>> 'iptables' and 'nftables' are competing technologies.  In CentOS 8,
>> firewalld's backend was switched from iptables to nftables.  So it
>> would be expected that the iptables command wouldn't have any rules
>> defined, it isn't being used by firewalld.
> 
> That is partially incorrect.  While iptables and nftables are two
> different in-kernel firewalls, the iptables CLI command is now a wrapper
> that can translate to the nftables backend for compatibility.
> 
> However, it can only manage a subset of nftables information (basically
> what it can create in the iptables back-compat mode).  The nftables
> rules created by firewalld don't fall into that category, so can't be
> viewed by iptables.
> 
> Instead, use the nft command, like "nft list ruleset" to see a dump of
> all current rules.

This sounds reasonable albeit it raises another question. How does the
netfilter workflow looks like when firewalld generated rules and 
iptables generated rules (coming from migration activities) are 
processed. How are both categories of rules interwoven? I assume taking
only the nftables path will be the cleanest and preferred one ... but
I can not avoid running some iptables tests.

--
Thanks,
Leon