Lu sur: https://www.linode.com/docs/guides/configure-firewall-with-ufw/
Il faut éditer à la main après avoir monté ton disque system dans /mnt
Edit UFW’s Configuration Files
Although simple rules can be added through the command line, there may be a time when more advanced or specific rules need to be added or removed. Prior to running the rules input through the terminal, UFW will run a file, before.rules, that allows loopback, ping, and DHCP. To add to alter these rules edit the /etc/ufw/before.rules file. A before6.rules file is also located in the same directory for IPv6.
An after.rule and an after6.rule file also exists to add any rules that would need to be added after UFW runs your command-line-added rules.
An additional configuration file is located at /etc/default/ufw. From here IPv6 can be disabled or enabled, default rules can be set, and UFW can be set to manage built-in firewall chains.