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How to fix the March 2017 Ubuntu DNS resolution issues

Posted March 22, 2017 48.6k views
UbuntuPHPFAQMiscellaneousWordPressEmailNetworkingDNS

As of March 20th, many Ubuntu users across the web were suddenly having DNS resolution issues pop up in their applications due to a bad update pushed out by Canonical (the maintainers of Ubuntu) which breaks DNS resolution after a few hours of uptime. Here’s the bug report where the issue was reported and triaged:

https://bugs.launchpad.net/ubuntu/+source/eglibc/+bug/1674532

This may have resulted in failures of your CMS to update/install plugins/install themes, failures to connect to external APIs, and/or error messages similar to the following:

Warning: file_get_contents(): php_network_getaddresses: getaddrinfo failed: No address associated with hostname

Could not resolve host: downloads.wordpress.org

cURL error 6: Could not resolve host: example.com in....

Fortunately Canonical has since been able to resolve the issue, but affected systems must update to acquire the fix. To do that, you’ll need DNS working, so if it’s currently down please first reboot your Droplet. Once DNS resolution is working as normal, please run:

sudo apt-get update
sudo apt-get upgrade

Then you can check your versions to ensure you’ve got the right ones. This can be done with:

sudo dpkg -l | grep "GNU C Library" | awk '{print $3}'

If you’re on Ubuntu 16.X, you should see output similar to the following:

# sudo dpkg -l | grep "GNU C Library" | awk '{print $3}'
2.23-0ubuntu7
2.23-0ubuntu7
2.23-0ubuntu7

If you’re on Ubuntu 14.X, you should see output similar to the following:

# sudo dpkg -l | grep "GNU C Library" | awk '{print $3}'
2.19-0ubuntu6.11
2.19-0ubuntu6.11

If you’re on Ubuntu 12.X, you should see output similar to the following:

# sudo dpkg -l | grep "GNU C Library" | awk '{print $3}'
2.15-0ubuntu10.17
2.15-0ubuntu10.17

If you see older versions of those packages, you’ll need to upgrade per the previous instructions to avoid this issue.

If you have further questions, please don’t hesitate to comment below or open a ticket! We’re happy to help :)

Regards,
Darian
Platform Support Advocate

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dwilkin
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dwilkin

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11 answers
drs5ma March 26, 2017

I am having some trouble still. DNS works but is extremely slow (~1min), I was able to sudo apt-get update and sudo apt-get upgrade and confirmed right version – but still having dns issues even after reboot (pinging any url fails, but pinging ip’s works fine)

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  • dwilkin March 26, 2017

    Hey there! Are you by chance in the NYC or SFO region? This could be due to a different problem with Google’s DNS, particularly if your IP address starts with 192.241. To resolve that problem, please try replacing the contents of /etc/resolv.conf with:

    nameserver 208.67.222.222
    nameserver 208.67.220.220

    Then saving that file. That should get you around the Google DNS problems until they’re resolved.

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    • reclaimhosting March 26, 2017

      This was definitely the case for us. Updating all packages didn’t fix the issue but switching to OpenDNS seems to be working a bit better. We’re still seeing some slow resolution times (~10 seconds to resolve an address) but no failures now. Would be curious to know if the Google DNS thing is widespread. We have quite a few servers in NYC.

      Reply Report
    • reclaimhosting March 26, 2017

      Turns out editing /etc/resolvconf/resolv.conf.d/base didn’t apply on our server (this was a WordPress Ubuntu image). That file was empty and adding OpenDNS to it just put 1 of the IPs below the two Google nameservers in /etc/resolv.conf. We had to edit /etc/network/interfaces.d/50-cloud-init.cfg and change the nameserver IPs there, then service networking restart and resolveconf -u and now we’re only using OpenDNS and things are loading much faster.

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      • dwilkin March 27, 2017

        Thanks so much for the update, and you’re right! I’ve edited the response to reflect a more temporary change that will avoid any permanent changes for those users affected by this problem.

        Reply Report
    • groundcontrol10000 March 27, 2017

      Worked for me even without executing apt-get update/upgrade.

      I’m running Wordpress on Ubuntu 12.04.5 and noticed my dashboard became almost completely unresponsive since yesterday. Some plugins returned cURL error 6: Couldn’t resolve host.

      BTW, no reboot is required after editing /etc/resolv.conf, you just save it.

      Reply Report
    • polesoft March 28, 2017

      Thanks, solved my problem in NYC2 region

      Reply Report
    • MattFnSmith July 12, 2018

      Thank you!!! Was having quite a headache with googles nameservers for some reason. Using this fixed everything!

      Reply Report
adamhanna17 March 22, 2017

Thank you, I hope this has solved my issue. We have been having intermittent issues connecting to the aws api as of 21st March receiving the ‘cURL error 6: Could not resolve host: example.com’ error message.

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graham23s March 22, 2017

Did the update, but still seeing the issue, do we need to reset anything after the update? :)

phpnetworkgetaddresses: getaddrinfo failed: No address associated with hostname (0)

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Webmater March 23, 2017

Thank you.

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zhanna March 23, 2017

This worked to get plugin updates and the dashboard news feeds working again on my WordPress site. Thank you!

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thiagogenehr March 27, 2017

I performed the procedure, but the problem is still occurring.

CURL error 28: Resolving timed out after 10521 milliseconds

My droplet is on the NYC1 server running a WordPress 4.7 on 16.04 image.

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  • dwilkin March 27, 2017

    It’s possible you’re being affected by another distinct issue with Google’s DNS that just popped up in the last 48 hours; particularly if your IP address starts with 192.241. To resolve that problem, please try replacing the contents of /etc/resolv.conf with:

    nameserver 208.67.222.222
    nameserver 208.67.220.220

    Then saving that file. That should get you around the Google DNS problems until they’re resolved.

    Reply Report
FrameworkStudios March 29, 2017

I spent 2 entire days working on this issue and fixed it in less than 2 minutes once I’d found this article. I was such a pain in the ass to figure out what was happening. Eventually I did realize that something was messed up with DNS but I spent 6 hours trying to find a problem with the UFW that didn’t exist. So stressful…

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  • dwilkin March 29, 2017

    I’m sorry to hear that! If you are a DO customer, please don’t hesitate to reach out to us when something like that happens, we’re happy to help!

    Reply Report
    • FrameworkStudios March 29, 2017

      I am, I believed it was something I had done because I was testing wordfence then I also had whitelisted a ton of IPs for cloudflare, MAXCDN, and ManageWP and disabled 80 and 443 to my hosts. I then had thought I somehow broke the UFW because I could never get back to a stable place after those changes. Even though I had removed them afterwards.
      At this point, all my UFW are working right with only 22 only and big list of whitelisted IP addresses.

      Reply Report
Strixy March 29, 2017

I had to edit the /etc/resolve.conf file to add name servers as recommended above.

That gave me the opportunity to upgrade Ubuntu. As suggested above, I am seeing the proper results.

sudo dpkg -l | grep “GNU C Library” | awk ’{print $3}’
2.23-0ubuntu7
2.23-0ubuntu7
2.23-0ubuntu7
2.23-0ubuntu7
2.23-0ubuntu7

Unfortunately, after a few hours the problem returns. Is there a fix for this situation?

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  • dwilkin March 30, 2017

    Sometimes applications will be holding an old version of the libraries and won’t let go of them until that application is restarted. As it’s tough to tell which ones are still using it, the easiest way is to just reboot. Could you try that and let me know if the problem comes back?

    Reply Report
reednj March 27, 2017

I didn’t realise that automatic updates were on that could break my server like this. How do I turn these updates off for 16.04??

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krishnadahal201 November 5, 2017

I am having same problem till now. Reported to support 2-3 times and they replied me everything is fine. My web application loads now in 10-15s whereas it used to load in 4-6s. It’s so frustrating.

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  • dwilkin November 14, 2017

    I’m sorry to hear that! What sort of error messages are you seeing that lead you to believe this is a DNS resolution issue? And could you try disabling any firewalls you’ve added just in case they’re blocking DNS lookups?

    Have you also tried changing your DNS resolvers to another provider to see if that helps?

    Reply Report
philipmoses January 29, 2018

DNS problem is preventing me from sending email, SMS and connecting with my spaces and adding objects into the space. This is happening after I updated my server based on your security email. Help me soon. All my users are affected. None of the above solution worked

This is the error message:
phpnetworkgetaddresses: getaddrinfo failed

The whole website works fine on development.

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  • dwilkin January 29, 2018

    I’m sorry to hear that Philip!

    It’s tough to help you troubleshoot an issue like that over the forums, could you open a ticket with our support team so they can help you out? Thanks so much!

    Reply Report
philipmoses January 29, 2018
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