/etc/netplan/01-network-manager-all.yaml

...
[DEVICE_NAME]:
...
    nameservers:
        addresses: [1.1.1.1, 9.9.9.9]
</code>
 
<WRAP center round info 60%>
**NOTE:**  The filename under /etc/netplan might be different.
</WRAP>
 
 
 
===== Global DNS Setting =====
 
==== Set the DNS ====
 
<file bash /etc/systemd/resolved.conf>
[Resolve]
DNS=9.9.9.9
FallbackDNS=149.112.112.112
DNSSEC=true
DNSOverTLS=opportunistic

sudo systemctl restart systemd-resolved.service

systemd-resolve --status

returns:

Global
    DNS Servers: 9.9.9.9
 
Link 3 [DEVICE_NAME]
      DNSSEC Setting: yes
    DNSSEC Supported: yes
         DNS Servers: 8.26.56.26
                      8.20.247.20