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Bug #74287 DNS Resolution appears broken with recent Ubuntu update
Submitted: 2017-03-21 21:33 UTC Modified: 2017-03-23 17:39 UTC
Avg. Score:4.8 ± 0.5
Reproduced:17 of 17 (100.0%)
Same Version:11 (64.7%)
Same OS:15 (88.2%)
From: jndockery at gmail dot com Assigned:
Status: Not a bug Package: Network related
PHP Version: 5.6.30 OS: Ubuntu 14.04.5 LTS
Private report: No CVE-ID: None
 [2017-03-21 21:33 UTC] jndockery at gmail dot com
After an automated update, PHP appears unable to resolve DNS entries

 - Other commands still resolve properly: ping, telnet, ldapsearch, curl
 - Affected 3 services on separate servers
 - Servers without unattended-upgrades (updated 2017-03-17) still functioning
 - Adding a manual entry in /etc/hosts allows DNS resolution

Affected service examples:
 - ldap_bind(): "Can't contact LDAP server"
 - PHP curl: "Could not resolve host: ..."
 - SMTP: "Connection could not be established with host"

Packages recently updated:

 - libgnutls-openssl27:amd64
 - multiarch-support:amd64
 - libfreetype6:amd64
 - libc-dev-bin:amd64
 - libc-bin:amd64
 - libc6:amd64
 - libgnutls26:amd64
 - libc6-dev:amd64

Start-Date: 2017-03-21  06:31:17
Upgrade: libgnutls-openssl27:amd64 (2.12.23-12ubuntu2.6, 2.12.23-12ubuntu2.7), multiarch-support:amd64 (2.19-0ubuntu6.9, 2.19-0ubuntu6.10), libfreetype6:amd64 (2.5.2-1ubuntu2.5, 2.5.2-1ubuntu2.6), libc-dev-bin:amd64 (2.19-0ubuntu6.9, 2.19-0ubuntu6.10), libc-bin:amd64 (2.19-0ubuntu6.9, 2.19-0ubuntu6.10), libc6:amd64 (2.19-0ubuntu6.9, 2.19-0ubuntu6.10), libgnutls26:amd64 (2.12.23-12ubuntu2.6, 2.12.23-12ubuntu2.7), libc6-dev:amd64 (2.19-0ubuntu6.9, 2.19-0ubuntu6.10)
End-Date: 2017-03-21  06:31:22

Thank you!

Test script:
  $url = "http://$_SERVER[HTTP_HOST]";
  $ch = curl_init();

Expected result:
no output

Actual result:
Could not resolve host:


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 [2017-03-21 21:55 UTC] spam2 at rhsoft dot net
and why don't you write a bugreport on the ubuntu bugtracker instead upstream? most likely some library update broke the PHP installation - both is from ubuntu and PHP 5.6 is more or less EOL at all

and another question: who does "automated updates" and then complains at upstream bugtrackers that some unattended downstream stuff broke whatever?
 [2017-03-21 22:46 UTC]
@rhsoft: It would be much appreciated if you could tone down your comments a bit. They are commonly passive aggressive, sometimes downright rude and contribute to a somewhat unpleasant atmosphere on this bug tracker.
 [2017-03-22 10:33 UTC] spam2 at rhsoft dot net
sorry, but i don't get how ideas like "oh, my distribution updated libc and something broke, i will report a bug on the victims upstream bugtracker" are growing
 [2017-03-22 11:16 UTC] alex at 1200wd dot com
For people like me that happened to stumble on this:

Checking my apt logs the following packages were updated at that time:

- libxml2
- libc-bin

This happened on an ubuntu 16.04 server with php7.
 [2017-03-22 13:14 UTC] frank at groenewoud dot me
Changelog libc-bin:
eglibc (2.19-0ubuntu6.11) trusty-security; urgency=medium

  * REGRESSION UPDATE: Previous update introduced ABI breakage in
    internal glibc query ABI
    - Back out patches/any/CVE-2015-5180-regression.diff
      (LP: #1674532)

 -- Steve Beattie <>  Tue, 21 Mar 2017 03:28:13 -0700

Bug 1674532:
After installing the libc6_2.19-0ubuntu6.10_amd64_udeb package during the automated install of ubuntu 14.04.5, the system was suddenly unable to resolve hostnames via dns. Installing -0ubuntu6.9 resolved the issue. Reinstalling -ubuntu6.10 broke the system again.

I note that -ubuntu6.10 was recently added to the archive.

I am currently unable to install Ubuntu 14.04.5.
 [2017-03-22 14:22 UTC] afrase at wddonline dot com
According to

The cause might be the fix of CVE-2016-3706: getaddrinfo: stack overflow in hostent conversion.
 [2017-03-22 17:37 UTC] jndockery at gmail dot com
-Status: Open +Status: Closed
 [2017-03-22 17:37 UTC] jndockery at gmail dot com
Thanks to all for the helpful resources - 

libc version 2.19-0ubuntu6.11 resolves the issue introduced in 2.19-0ubuntu6.10.
 [2017-03-22 21:16 UTC] mateus at simplehost dot com dot br
I saw this same behavior in 8 Ubuntu servers, with automated security updates.
 [2017-03-22 21:59 UTC] spam2 at rhsoft dot net
> I saw this same behavior in 8 Ubuntu servers, with automated security update

what is a "ubuntu server"? :-)

joke aside - and hence when everything but not PHP is update dand PHP has a problem than it#s not the responsibility of PHP and when you get your PHP from your distribution it is NEVER a php upstream bug wehan some random package is updated and php breaks
 [2017-03-23 17:39 UTC]
-Status: Closed +Status: Not a bug
 [2017-03-24 14:02 UTC] danielpetrak1 at gmail dot com
I have experienced same issue, i resolved the problem. Howerver we use Plesk Panel. Via Plesk I changed PHP version and then changed it back to same version. Problem fixed, probably some PHP config got rebuiled by that.
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