Ubuntu Server DNS Resolver Issues


March 21st, 2017


This morning many people, including Laravel News, are experiencing that their sites are erroring when communicating with third party systems. The hostnames couldn’t be resolved and causing all those to fail.

The apparent fix is to restart either PHP-FPM, Apache, or Nginx. If you are using Forge you can SSH in and run:

1sudo service php7.0-fpm restart

Replacing “7.0” with your installed PHP version, or restart the Nginx service from the Forge admin.

I haven’t been able to pinpoint the actual cause but on social media, some are saying it’s related to an Ubuntu nightly security update.

In my tests it was just web requests, anything ran through the CLI would still work fine, but that meant that my Bugsnag errors couldn’t be logged, and all the API calls failed.

Update: Based on an AWS forum thread they are reporting that is likely to have been caused by a recent libc6 security update on Ubuntu as there was a patch to the DNS resolution code.

Update Mar 22, 2017: In today’s Ubuntu Security Notice USN-3239-2 they have reverted the change that caused issues yesterday. That means that long-running services that were restarted to compensate for USN-3239-1 update will need to be restarted again.

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Eric L. Barnes

Eric is the creator of Laravel News and has been covering Laravel since 2012.

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