Ubuntu 20.04 DNS Not Resolving

jellybeard999 · 15 Dec 2021 at 17:41

Clean install of Ubuntu 20.04 LTS command line on Hyper-V. I've set a static IP and pointed the DNS to 8.8.8.8 in the "01-netcfg.yaml" file as below.

Code:

network:
  version: 2
  renderer: networkd
  ethernets:
    eth0:
      dhcp4: no
      addresses: [staticip/24]
      gateway: routerip
      nameservers:
        addresses: [8.8.8.8]

The static IP seems to work fine, can connect over SSH etc, however, DNS don't seem to resolve - eg apt-get update results in a "Temporary failure resolving" error.

If I edit the nameserver in resolv.conf to 8.8.8.8, DNS work for a very short period of time, then the file seems to revert back to default 127.0.0.53 and it doesn't work again

Any ideas?

DNS was working find on 18.04 and I don't think I've done anything differently. End goal is to point the DNS to my router, which has the DNS configured for pihole - this IP doesn't work either, but sticking with google DNS for now until I get it working.

The DNS on the rest of the network is working fine.

Armageus · 15 Dec 2021 at 18:13

After editing the config have you applied it?

sudo netplan apply

https://phoenixnap.com/kb/ubuntu-dns-nameservers

jellybeard999 · 15 Dec 2021 at 18:39

Armageus said:
After editing the config have you applied it?

sudo netplan apply

https://phoenixnap.com/kb/ubuntu-dns-nameservers

Thanks, but yes, I've applied it

jellybeard999 · 17 Dec 2021 at 14:40

Any ideas anyone?

the-evaluator · 24 Dec 2021 at 16:46

This is working for me on 20.04 LTS:

Code:

network:
    ethernets:
        ens160:
            addresses:
            - 192.168.8.3/24
            gateway4: 192.168.8.1
            nameservers:
                addresses:
                - 8.8.8.8
                - 8.8.4.4
                search:
                - mydomain.com
            optional: true
    version: 2

the-evaluator · 24 Dec 2021 at 16:47

Also, check that you haven't got any other config files in /etc/netplan that might be replacing your config.

jellybeard999 · 26 Dec 2021 at 21:06

Reinstalled from scratch and entered the IP addresses during the installation process. All worked OK. Not sure what went wrong previously, but at least it's sorted now.

smogsy · 5 Jan 2022 at 15:46

jellybeard999 said:
Reinstalled from scratch and entered the IP addresses during the installation process. All worked OK. Not sure what went wrong previously, but at least it's sorted now.

had this issue before and the install had written hidden character to the config. move the file recreate job done. reported it a few months back.

ecksmen · 8 Jan 2022 at 09:27

Was the interface "eth0" ? if you do "ip link show" I would have expected it to be in the format of "enpXsY" than eth0 of older days.

Retro6 · 26 Feb 2022 at 02:24

Linux is going down the toilet