Question

8

Ubuntu 21.10 switched to nftables, so why is iptables still available?

rated 0 times [ 8] [ 0] / answers: 1 / hits: 11440 / 2 Years ago, sun, april 3, 2022, 10:27:14

nftables is now the default backend for the firewall.

However, having installed Ubuntu 21.10, I can see I still have iptables (and ufw) installed by default:

m@m-VirtualBox:~$ whereis iptables



iptables: /usr/sbin/iptables /usr/share/iptables /usr/share/man/man8/iptables.8.gz



m@m-VirtualBox:~$ whereis ufw



ufw: /usr/sbin/ufw /usr/lib/ufw /etc/ufw /usr/share/ufw /usr/share/man/man8/ufw.8.gz

Why does this happen?

As far as I'm aware, ufw is a wrapper around iptables, not nftables.

Can I safely use these commands? Or should I take care to never type iptables or ufw in the terminal?

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llianconclad

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answered 2 Years ago ugeeport · Accepted Answer

After your whereis iptables command, you should follow the files. Example, from a 20.04 server:

doug@s19:~$ whereis iptables

iptables: /usr/sbin/iptables /usr/share/iptables /usr/share/man/man8/iptables.8.gz

doug@s19:~$ ls -l /usr/sbin/iptables

lrwxrwxrwx 1 root root 26 Jan 23  2020 /usr/sbin/iptables -> /etc/alternatives/iptables

doug@s19:~$ ls -l /etc/alternatives/iptables

lrwxrwxrwx 1 root root 22 Apr 18  2021 /etc/alternatives/iptables -> /usr/sbin/iptables-nft

doug@s19:~$ ls -l /usr/sbin/iptables-nft

lrwxrwxrwx 1 root root 17 Feb 28  2020 /usr/sbin/iptables-nft -> xtables-nft-multi

doug@s19:~$ ls -l /usr/sbin/xtables-nft-multi

-rwxr-xr-x 1 root root 220488 Feb 28  2020 /usr/sbin/xtables-nft-multi

So, iptables is actually using nftables.

nftables can interpret iptables syntax.