Plugins (for example, iptables-persistent) to load and save filter rules. Netfilter-persistent does no work on its own. If you only install netfilter-persistent, you will find that rules are not correctly applied at boot, as per the README netfilter-persistent and its plugins If you only install iptables-persistent, you won't get the service definition file for correct handling in systemd, eg /lib/systemd/system/rvice The two packages are similar, but provide slightly different functionality. Ip6tables-restore < /etc/iptables/rules.v6

If you ever find that your rules aren't correctly applied at boot, you can run these commands to test that there are not errors in your config files: iptables-restore < /etc/iptables/rules.v4 Other commands that might be useful: netfilter-persistent save

Then edit the rules in /etc/iptables/rules.v If you would like your Ubuntu firewall to function in a similar way to RedHat/Fedora, in Ubuntu 18.04 20.04 22.04, you probably want these: sudo apt install iptables-persistent netfilter-persistent

Restart iptables