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I've got a RPi4 and I'm trying to configure ufw. The problem is that I get this error
ERROR: Couldn't determine iptables version
The versions of iptables and ufw are
iptables 1.8.2-4
libnftables0:armhf 0.9.0-2
libnftnl11:armhf 1.1.2-2
nftables 0.9.0-2
ufw 0.36-1
Linux version is Linux rP15 4.19.50-v7l+
Any ideas?
I found the solution. Buster comes with two iptables flavours
> $ update-alternatives --list iptables
/usr/sbin/iptables-legacy
/usr/sbin/iptables-nft
By default it uses iptables-nft. When changes to iptables-legacy
sudo update-alternatives --set iptables /usr/sbin/iptables-legacy
it works with UFW without problems after reboot.
I experienced the same problem immediately after installing ufw:
$ sudo ufw status
ERROR: Couldn't determine iptables version
But after rebooting (without changing any other settings) it started working (as suggested here):
$ sudo ufw status
Status: active
$ update-alternatives --display iptables | grep currently
link currently points to /usr/sbin/iptables-nft
$ uname -a
Linux raspberrypi 5.10.11+ #1399 Thu Jan 28 12:02:28 GMT 2021 armv6l GNU/Linux
$ lsb_release -a
No LSB modules are available.
Distributor ID: Raspbian
Description: Raspbian GNU/Linux 10 (buster)
Release: 10
Codename: buster
$ dpkg -s ufw | grep Version
Version: 0.36-1
$ dpkg -s iptables | grep Version
Version: 1.8.2-4
I'm not sure, but I think this Debian bug is related. If so, it's supposed to be fixed in Debian's ufw package's 0.36-3 version.
Buster uses nftables.
I haven’t tried this, but it is supposed to support iftables commands.
It is possible to revert, but you may be better to look for an updated tutorial
