Afin de contourner la configuration DNS de ma livebox, j'ai voulu utiliser les résolveurs fournis par FDN (https://www.fdn.fr/actions/dns/) et les inscrire en dur dans le système. J'ai donc suivi la doc fournie par FDN : https://git.fdn.fr/fdn-public/wiki/-/bl ... fig_dns.md, ainsi que la page dédié sur Archwiki : https://wiki.archlinux.org/title/Systemd-resolved (article 2.1)
J'ai donc créé le lien symbolique à l'aide de la commande
ln -sf ../run/systemd/resolve/stub-resolv.conf /etc/resolv.conf
/etc/resolv.conf
# This is /run/systemd/resolve/stub-resolv.conf managed by man:systemd-resolved(8).
# Do not edit.
#
# This file might be symlinked as /etc/resolv.conf. If you're looking at
# /etc/resolv.conf and seeing this text, you have followed the symlink.
#
# This is a dynamic resolv.conf file for connecting local clients to the
# internal DNS stub resolver of systemd-resolved. This file lists all
# configured search domains.
#
# Run "resolvectl status" to see details about the uplink DNS servers
# currently in use.
#
# Third party programs should typically not access this file directly, but only
# through the symlink at /etc/resolv.conf. To manage man:resolv.conf(5) in a
# different way, replace this symlink by a static file or a different symlink.
#
# See man:systemd-resolved.service(8) for details about the supported modes of
# operation for /etc/resolv.conf.
nameserver 127.0.0.53
options edns0 trust-ad
search home
/etc/systemd/resolved.conf
[Resolve]
DNS=80.67.169.12#ns0.fdn.fr 2001:910:800::12#ns0.fdn.fr
FallbackDNS=9.9.9.9#dns.quad9.net 149.112.112.112#dns.quad9.net 2620:fe::fe#dns.quad9.net 262 80.67.169.40#ns1.fdn.fr 2001:910:800::40#ns>
DNSOverTLS=yes
[DHCPv4]
UseDNS=false
Mon problème : après chaque démarrage/redémarrage, mon
/etc/resolv.conf
sudo systemctl restart systemd-resolved
sudo systemctl restart NetworkManager
Je précise ne pas être un expert, merci pour votre indulgence

bonne journée