resolv.conf - No DNS servers known
Solution 1:
If /etc/netplan
is empty then netplan does not configure your network.
Your network is probably configured in old ifup/ifdown style.
That means you find the network configuration in /etc/network/interfaces
.
In addition there is systemd-resolve with its DNS configuration file /etc/systemd/resolved.conf
where you can put your DNS configuration in.
[Resolve]
DNS=8.8.4.4 8.8.8.8 2001:4860:4860::8844 2001:4860:4860::8888
#FallbackDNS=
Domains=example.com
#LLMNR=no
#MulticastDNS=no
#DNSSEC=no
#Cache=yes
#DNSStubListener=yes
You can check your DNS settings with
systemd-resolve --status
You can restart systemd-resolve with
systemctl restart systemd-resolved
Alternatively you can put your settings in /etc/resolvconf/resolv.conf.d/tail
which will be added to /run/resolvconf/resolv.conf
during boot.
Solution 2:
Ubuntu 20.04 uses /etc/netplan to set DNS. Do you have nameservers section in your /etc/netplan/?.yaml file?
yaml-file should have a section similar like this:
nameservers:
addresses:
- 8.8.8.8
- 2001:4860:4860::8888
resolve.conf is generated from netplan during boot and should should look like this.
nameserver 127.0.0.53
options edns0 trust-ad
search example.com
There is also a /etc/systemd/resolved.conf where static configuration may be strored. You can read more details man resolved.conf
Furthermore you can investigate journalctl -b and search for systemd-resolved messages.