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Thread: Temporary failure in name resolution

  1. #1
    Join Date
    May 2018
    Beans
    3

    Temporary failure in name resolution

    Hello all,

    I'm setting up a ubuntu server on my network to use my local windows DNS server for name resolution (located at 192.168.40.20). When I try to ping other machines on my network from the ubuntu server, I get the following error: Temporary failure in name resolution. This is true both if I try the qualified or full name.


    I can dig other machines by specifying the name server like

    # dig @192.168.40.20 <hostname>

    which works just fine, so the DNS server itself is working fine. Also, every other machine on the network is using the DNS server and working just fine.


    I've set up my /etc/netplan/50-cloud-init.yaml file as follows

    network:
    version: 2
    ethernets:
    ens160:
    addresses: [192.168.40.6/24]
    gateway4: 192.168.40.1
    nameservers:
    addresses: [192.168.40.20]

    and run sudo netplan apply (also I've rebooted)

    when I run systemd-resolve --status I see the following

    Global
    DNSSEC NTA: 10.in-addr.arpa
    16.172.in-addr.arpa
    168.192.in-addr.arpa
    17.172.in-addr.arpa
    18.172.in-addr.arpa
    19.172.in-addr.arpa
    20.172.in-addr.arpa
    21.172.in-addr.arpa
    22.172.in-addr.arpa
    23.172.in-addr.arpa
    24.172.in-addr.arpa
    25.172.in-addr.arpa
    26.172.in-addr.arpa
    27.172.in-addr.arpa
    28.172.in-addr.arpa
    29.172.in-addr.arpa
    30.172.in-addr.arpa
    31.172.in-addr.arpa
    corp
    d.f.ip6.arpa
    home
    internal
    intranet
    lan
    local
    private
    test


    Link 7 (idrac)
    Current Scopes: none
    LLMNR setting: yes
    MulticastDNS setting: no
    DNSSEC setting: no
    DNSSEC supported: no


    Link 2 (ens160)
    Current Scopes: DNS
    LLMNR setting: yes
    MulticastDNS setting: no
    DNSSEC setting: no
    DNSSEC supported: no
    DNS Servers: 192.168.40.20



    I'm not sure what I've got misconfigured. Any help would be appreciated.

    Thanks!
    Kevin

  2. #2
    Join Date
    Feb 2009
    Location
    Dallas, TX
    Beans
    7,796
    Distro
    Ubuntu 16.04 Xenial Xerus

    Re: Temporary failure in name resolution

    Hi kevin.nelson. Welcome to forum

    Could you run these commands, and post back the results? (you can copy/paste the text)
    Code:
    apt policy netplan
    
    ip address
    
    ip route
    
    cat /etc/network/interfaces
    
    cat /etc/resolv.conf
    
    cat /etc/nsswitch.conf 
    
    nslookup ubuntu.com
    
    dig ubuntuforums.org
    
    ping 192.168.40.20
    Regards.

  3. #3
    Join Date
    May 2018
    Beans
    3

    Re: Temporary failure in name resolution

    Hi papibe, thanks for the response.

    I've provided the results which you requested below.

    Additionally, I noticed that if I manually add 192.168.40.20 as a nameserver to /etc/resolv.conf, name resolution works as expected. However, the comments in the file say not to edit because the file is managed by systemd-resolved. Therefore, I think my specific question becomes how to add a nameserver to systemd-resolved. I thought this was done by configuring a nameserver in /etc/netplan/50-cloud-init.yaml, but that does not work.

    Code:
    # apt policy netplan
    
    netplan:
      Installed: (none)
      Candidate: 1.10.1-5build1
      Version table:
         1.10.1-5build1 500
            500 http://archive.ubuntu.com/ubuntu bionic/universe amd64 Packages
    Code:
    # ip address
    
    
    1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
        link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
        inet 127.0.0.1/8 scope host lo
           valid_lft forever preferred_lft forever
        inet6 ::1/128 scope host
           valid_lft forever preferred_lft forever
    2: ens160: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
        link/ether 00:50:56:8f:44:e6 brd ff:ff:ff:ff:ff:ff
        inet 192.168.40.6/24 brd 192.168.40.255 scope global ens160
           valid_lft forever preferred_lft forever
        inet6 fe80::250:56ff:fe8f:44e6/64 scope link
           valid_lft forever preferred_lft forever
    3: idrac: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
        link/ether 44:a8:42:10:6c:b1 brd ff:ff:ff:ff:ff:ff

    Code:
    
    # ip route
    
    default via 192.168.40.1 dev ens160 proto static
    192.168.40.0/24 dev ens160 proto kernel scope link src 192.168.40.6
    
    Code:
    
    # cat /etc/network/interfaces
    
    # ifupdown has been replaced by netplan(5) on this system.  See
    # /etc/netplan for current configuration.
    # To re-enable ifupdown on this system, you can run:
    #    sudo apt install ifupdown
    
    Code:
    
    # cat /etc/resolv.conf
    
    # This file is managed by man:systemd-resolved(8). Do not edit.
    #
    # This is a dynamic resolv.conf file for connecting local clients to the
    # internal DNS stub resolver of systemd-resolved. This file lists all
    # configured search domains.
    #
    # Run "systemd-resolve --status" to see details about the uplink DNS servers
    # currently in use.
    #
    # Third party programs must not access this file directly, but only through the
    # symlink at /etc/resolv.conf. To manage man:resolv.conf(5) in a different way,
    # replace this symlink by a static file or a different symlink.
    #
    # See man:systemd-resolved.service(8) for details about the supported modes of
    # operation for /etc/resolv.conf.
    
    
    nameserver 127.0.0.53
    
    Code:
    
    # cat /etc/nsswitch.conf
    
    # /etc/nsswitch.conf
    #
    # Example configuration of GNU Name Service Switch functionality.
    # If you have the `glibc-doc-reference' and `info' packages installed, try:
    # `info libc "Name Service Switch"' for information about this file.
    
    
    passwd:         compat systemd
    group:          compat systemd
    shadow:         compat
    gshadow:        files
    
    
    hosts:          files dns
    networks:       files
    
    
    protocols:      db files
    services:       db files
    ethers:         db files
    rpc:            db files
    
    
    netgroup:       nis
    
    Code:
    # nslookup ubuntu.com
    
    Server:         127.0.0.53
    Address:        127.0.0.53#53
    
    
    Non-authoritative answer:
    Name:   ubuntu.com
    Address: 91.189.94.40
    Code:
    
    # dig ubuntuforums.com
    
     <<>> DiG 9.11.3-1ubuntu1-Ubuntu <<>> ubuntuforums.com
    ;; global options: +cmd
    ;; Got answer:
    ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 34584
    ;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 1
    
    
    ;; OPT PSEUDOSECTION:
    ; EDNS: version: 0, flags:; udp: 65494
    ;; QUESTION SECTION:
    ;ubuntuforums.com.              IN      A
    
    
    ;; ANSWER SECTION:
    ubuntuforums.com.       598     IN      A       91.189.94.12
    ubuntuforums.com.       598     IN      A       91.189.94.16
    
    
    ;; Query time: 162 msec
    ;; SERVER: 127.0.0.53#53(127.0.0.53)
    ;; WHEN: Wed May 09 14:05:14 UTC 2018
    ;; MSG SIZE  rcvd: 77
    Code:
    
    # ping 192.168.40.20
    
    64 bytes from 192.168.40.20: icmp_seq=1 ttl=128 time=0.132 ms
    64 bytes from 192.168.40.20: icmp_seq=2 ttl=128 time=0.101 ms
    64 bytes from 192.168.40.20: icmp_seq=3 ttl=128 time=0.165 ms
    
    --- 192.168.40.20 ping statistics ---
    3 packets transmitted, 3 received, 0% packet loss, time 2052ms
    rtt min/avg/max/mdev = 0.101/0.132/0.165/0.029 ms




  4. #4
    Join Date
    Feb 2009
    Location
    Dallas, TX
    Beans
    7,796
    Distro
    Ubuntu 16.04 Xenial Xerus

    Re: Temporary failure in name resolution

    Thanks.

    Did you install netplan.io instead of netplan? Cloud you run this command?
    Code:
    apt policy netplan.io
    127.0.0.53 in your resolv.conf makes me think you had NetworkManager installed. Is this a server edition or a desktop serving as a server?

    If this is a server edition, it looks like systemd-resolved is conflicting with netplan. Try this:
    Code:
     sudo systemctl disable systemd-resolved
    and then reboot
    Code:
    sudo reboot
    Hope it helps. Let us know how it goes.
    Regards.

  5. #5
    Join Date
    May 2018
    Beans
    3

    Re: Temporary failure in name resolution

    Hello,

    Thanks for the response.

    I was able to fix my problem by editing /etc/systemd/resolved.conf and adding the DNS server there. I also had to add the local domain name that the DNS server is handling or it wouldn't resolve. However, everything seems to work now.

    To answer your question, this is ubuntu server addition. The server is freshly installed with all the default packages. It looks like netplan.io is installed instead of netplan (i'm not familiar with the differences).

    Thank you for your help!

  6. #6
    Join Date
    Oct 2016
    Beans
    1

    Re: Temporary failure in name resolution

    Quote Originally Posted by papibe View Post
    If this is a server edition, it looks like systemd-resolved is conflicting with netplan. Try this:
    Code:
     sudo systemctl disable systemd-resolved
    and then reboot
    Code:
    sudo reboot
    Hope it helps.
    I've approached this issue when upgrading to 18 from 16, and disabling systemd-resolved as instructed above, solved the issue.

    Thanks @papibe!

  7. #7
    Join Date
    May 2007
    Location
    Ontario
    Beans
    480
    Distro
    Ubuntu

    Re: Temporary failure in name resolution

    My Ubuntu 18.04 DigitalOcean droplet server is toast as of two days ago and I have no idea why or what changed. I first noticed the issue when my vhosts became inaccessible. Then I tried to ssh in from my localhost (with rsa keys in place) and the ssh session timed out completely. The only way I can access my server right now is from the QEMU web front end provided by DigitalOcean in my web browser.

    Attached you can view the original apt errors I am trying to deal with.

    I would like to provide the output from @papibe’s suggested commands, but it appears there is no way for me to copy text from my web terminal emulator like I ordinarily would from a local gnome-terminal session. So I have taken screenshots of all my output so you folks can see.

    As suggested elsewhere, I tried temporarily turning off my firewall and running apt update and which didn’t fix the issue. I promptly turned my firewall back on.

    What worked for @medikoo2 (disabling systemd-resolved) didn’t work for me.

    What else would you people recommend I try next?
    Attached Images Attached Images
    My rig:
    IBM Personal System/2 Model 30-286 - - Intel 80286 (16 bit) 10 Mhz - - 1MB DRAM - - Integrated VGA Display adapter
    1.44MB capacity Floppy Disk - - PS/2 keyboard (no mouse)

  8. #8
    Join Date
    May 2007
    Location
    Ontario
    Beans
    480
    Distro
    Ubuntu

    Re: Temporary failure in name resolution

    By the way, a similar issue described over on DigitalOcean called, "Apt-get update failing with unable to resolve error"

    A veteran forum member there suggested:
    Code:
    sudo apt-get clean
    cd /var/lib/apt
    sudo mv lists lists.old
    sudo mkdir -p lists/partial
    sudo apt-get clean
    sudo apt-get update
    This didn’t fix the issue
    My rig:
    IBM Personal System/2 Model 30-286 - - Intel 80286 (16 bit) 10 Mhz - - 1MB DRAM - - Integrated VGA Display adapter
    1.44MB capacity Floppy Disk - - PS/2 keyboard (no mouse)

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