How do I debug "Temporary failure in name resolution" error after upgrading to Xubuntu 19.04 desktop?

networking xubuntu network-manager dns 19.04

9,086

I suggest that you recreate the missing netplan file; from the terminal:

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

Add the following:

network:
  version: 2
  renderer: NetworkManager

The spacing and indentation are critical and must be correct. Proofread carefully twice. Save (Ctrl+o followed by Enter) and exit (Ctrl+x) the text editor. Follow with:

sudo netplan generate
sudo netplan apply

Next, in your case, resolv.conf is not pointing to systemd as expected. Therefore, I suggest that you remove and recreate the link:

sudo rm -f /etc/resolv.conf
sudo ln -s /run/systemd/resolve/stub-resolv.conf /etc/resolv.conf

Reboot and tell us if there is any improvement.

9,086

Author by

Mark Northrop

Updated on September 18, 2022

Comments

Mark Northrop almost 2 years

I recently upgraded Xubuntu from 18.10 to 19.04, and have started seeing the "Temporary failure in name resolution" error whenever I try to ping a domain name since then. I am using a desktop computer with a single ethernet connection to a modem/router. I have been upgrading the same install of Xubuntu for years; I'm not sure when I last did a fresh install.

Pinging an IP address works just fine, only pinging domain names causes this error.

If I disconnect and then reconnect the ethernet connection using the Network Manager panel applet (screenshot below), the error goes away and the internet connection works until I reboot the computer.

These are my connection's settings:

On a fresh boot, these are the abridged results of a few commands that I've run to try to diagnose the issue before fixing the issue by disconnecting and reconnecting:

$ systemd-resolve --status

Link 2 (eth0)
      Current Scopes: DNS
DefaultRoute setting: yes
       LLMNR setting: yes
MulticastDNS setting: no
  DNSOverTLS setting: no
      DNSSEC setting: no
    DNSSEC supported: no
         DNS Servers: 8.8.8.8
                      8.8.4.4
          DNS Domain: ~.

$ nmcli device show eth0

IP4.ADDRESS[1]:                         192.168.1.8/24
IP4.GATEWAY:                            192.168.1.1
IP4.ROUTE[1]:                           dst = 0.0.0.0/0, nh = 192.168.1.1, mt = 100
IP4.ROUTE[2]:                           dst = 192.168.1.0/24, nh = 0.0.0.0, mt = 100
IP4.ROUTE[3]:                           dst = XXX.XXX.0.0/16, nh = 0.0.0.0, mt = 1000
IP4.DNS[1]:                             8.8.8.8
IP4.DNS[2]:                             8.8.4.4

$ systemctl status resolvconf

● resolvconf.service - Nameserver information manager
   Loaded: loaded (/lib/systemd/system/resolvconf.service; enabled; vendor preset: enabled)
   Active: active (exited) since Tue 2019-08-06 10:09:40 CEST; 6min ago

$ systemctl status NetworkManager

● NetworkManager.service - Network Manager
   Loaded: loaded (/lib/systemd/system/NetworkManager.service; enabled; vendor preset: enabled)
   Active: active (running) since Tue 2019-08-06 10:10:20 CEST; 5min ago
...
Aug 06 10:10:31 xxxx NetworkManager[1136]: <info>  [1565079031.8637] device (eth0): state change: ip-check -> secondaries (reason 'none', sys-iface-state: 'managed')
Aug 06 10:10:31 xxxx NetworkManager[1136]: <info>  [1565079031.8640] device (eth0): state change: secondaries -> activated (reason 'none', sys-iface-state: 'managed')
Aug 06 10:10:31 xxxx NetworkManager[1136]: <info>  [1565079031.8646] manager: NetworkManager state is now CONNECTED_LOCAL
Aug 06 10:10:32 xxxx dhclient[1397]: bound to 192.168.1.8 -- renewal in 37516 seconds.
Aug 06 10:10:32 xxxx NetworkManager[1136]: <info>  [1565079032.2838] manager: NetworkManager state is now CONNECTED_SITE
Aug 06 10:10:32 xxxx NetworkManager[1136]: <info>  [1565079032.2840] policy: set 'Wired connection 1' (eth0) as default for IPv4 routing and DNS
Aug 06 10:10:32 xxxx NetworkManager[1136]: <info>  [1565079032.2844] device (eth0): Activation: successful, device activated.
Aug 06 10:10:32 xxxx NetworkManager[1136]: <info>  [1565079032.2851] manager: NetworkManager state is now CONNECTED_GLOBAL
Aug 06 10:10:32 xxxx NetworkManager[1136]: <info>  [1565079032.2856] manager: startup complete
Aug 06 10:12:14 xxxx NetworkManager[1136]: <info>  [1565079134.0454] agent-manager: req[0x56068d7b9090, :1.89/org.freedesktop.nm-applet/1000]: agent registered

My netplan config directory is empty:

$ ls /etc/netplan -a

. ..

I don't know whether /etc/network/interfaces is still being used:

$ cat /etc/network/interfaces

# interfaces(5) file used by ifup(8) and ifdown(8)
auto lo
iface lo inet loopback

# auto eth0
# iface eth0 inet dhcp

Do you have any suggestions on how I could troubleshoot this issue? I would like the DNS to work without having to disconnect and reconnect the ethernet connection after every boot. Thanks!

Edit #1

$ ls -al /etc/resolv.conf

lrwxrwxrwx 1 root root 29 Jun 30  2015 /etc/resolv.conf -> ../run/resolvconf/resolv.conf

Edit #2

These are the contents of /etc/resolv.conf immediately after boot:

$ cat /etc/resolv.conf 
# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
#     DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
# 127.0.0.53 is the systemd-resolved stub resolver.
# run "systemd-resolve --status" to see details about the actual nameservers.

These are the contents of /etc/resolv.conf after disconnecting and re-connecting ethernet connection:

# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
#     DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
# 127.0.0.53 is the systemd-resolved stub resolver.
# run "systemd-resolve --status" to see details about the actual nameservers.

nameserver 127.0.0.53

chili555 almost 5 years

Please edit your question to show the result of the terminal command: ls -al /etc/resolv.conf
Mark Northrop almost 5 years

@chili555 Thank you for your response. I've added the result of ls -al /etc/resolv.conf
Elias almost 5 years

Possibly related: askubuntu.com/q/1163183/874649
Mark Northrop almost 5 years

@Elias Thanks for your comment. It appears there might be some similarity. I've updated my question with the contents of /etc/resolv.conf.

Mark Northrop almost 5 years

I'll try this. I've edited my question with the results of cat /etc/resolv.conf immediately after boot, and also after I've disconnected and re-connected the ethernet connection. Would you still suggest removing /etc/resolv.conf and linking it to /run/systemd/resolve/stub-resolv.conf instead?
chili555 almost 5 years

Yes, please do so.
Mark Northrop almost 5 years

Following these instructions solved the problem. The DNS is now working without issue from boot. @chili555 Thanks for your help!