Re: [CentOS] firewalld / iptables / nftables

2020-06-09 Thread Leon Fauster via CentOS

Am 09.06.20 um 15:27 schrieb Chris Adams:

Once upon a time, Jonathan Billings  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

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Re: [CentOS] firewalld / iptables / nftables

2020-06-09 Thread Chris Adams
Once upon a time, Jonathan Billings  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.

-- 
Chris Adams 
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Re: [CentOS] firewalld / iptables / nftables

2020-06-09 Thread Stephen John Smoogen
On Tue, 9 Jun 2020 at 08:19, Leon Fauster via CentOS 
wrote:

> Despite that the migration of our applications comes with a significant
> workload. It seems that also every aspect of common services had changed
> with EL8.
>
> In EL8 firewalld uses nftables as backend. I wonder why iptables does
> not list any rules while also configured to use nftables as backend.
>
> # iptables -V
> iptables v1.8.2 (nf_tables)
>
>
> # firewall-cmd --list-all |egrep -o '22|ssh'
> ssh
>
>
Maybe it's only defined to work for ipv6? Shouldn't there be 2 entries for
ssh?


> # nft list ruleset | egrep -o '22|ssh'
> ssh
>
> # iptables -L -n | egrep -o '22|ssh'
> 
>
> Any hints?
>
> --
> Leon
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>


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Re: [CentOS] firewalld / iptables / nftables

2020-06-09 Thread Jonathan Billings
On Tue, Jun 09, 2020 at 02:19:17PM +0200, Leon Fauster via CentOS wrote:
>
> Despite that the migration of our applications comes with a significant
> workload. It seems that also every aspect of common services had changed
> with EL8.
> 
> In EL8 firewalld uses nftables as backend. I wonder why iptables does not
> list any rules while also configured to use nftables as backend.
> 
> # iptables -V
> iptables v1.8.2 (nf_tables)
> 
> 
> # firewall-cmd --list-all |egrep -o '22|ssh'
> ssh
> 
> # nft list ruleset | egrep -o '22|ssh'
> ssh
> 
> # iptables -L -n | egrep -o '22|ssh'
> 
> 
> Any hints?

'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.

-- 
Jonathan Billings 
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[CentOS] firewalld / iptables / nftables

2020-06-09 Thread Leon Fauster via CentOS
Despite that the migration of our applications comes with a significant 
workload. It seems that also every aspect of common services had changed 
with EL8.


In EL8 firewalld uses nftables as backend. I wonder why iptables does 
not list any rules while also configured to use nftables as backend.


# iptables -V
iptables v1.8.2 (nf_tables)


# firewall-cmd --list-all |egrep -o '22|ssh'
ssh

# nft list ruleset | egrep -o '22|ssh'
ssh

# iptables -L -n | egrep -o '22|ssh'


Any hints?

--
Leon
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