Thank you for your comment. When I now run grep 8.8.8.8 /etc/resolv.confnothing appears. Before that "nameserver 8.8.8.8" appeared. After installing unbound, your suggested command brings this result:
echo nameserver 127.0.0.1 > /etc/resolv.conf && chattr +i /etc/resolv.conf bash: /etc/resolv.conf: Permission deniedThe content of /etc/resolv.conf is only "nameserver 127.0.0.1". RESOLVCONF_FORWARDERS from /etc/default/unbound was successfully changed to false.
