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I recently upgraded my ubuntu and suddenly lost DNS. By the looks of it, its related to https://bugs.launchpad.net/ubuntu/+source/eglibc/+bug/1674532. But I cannot run the update to fix the issue because it can't use DNS to conduct the update. Is there any documentation out there on how to get the DNS working again so i can run the update and fix the issue? I have tried changing the DNS server and everything and nothing is working.

cat /etc/resolv.conf

nameserver 8.8.8.8  
nameserver 8.8.4.4

cat /etc/NetworkManager/NetworkManager.conf

[main]  
plugins=ifupdown,keyfile,ofono  
dns=dnsmasq

[ifupdown]  
managed=false

dpkg -l dns | grep ii

ii avahi-dns confd      0.6.32~rc+dfsg-1ubuntu2 amd64   Avahi DNS configuration tool  
ii dnsmasq-base         2.75-1ubuntu0.16.04.1   amd64   Small caching DNS proxy and DHCP/TFTP Server  
ii dnsutils             1:9.10.3.dfsg.p4-8ubuntu1.5 amd64   Clients Provided with BIND  
ii libavahi-compact-libdnssd1:amd64    0.6.32~rc+dfsg-1ubuntu2   amd64   Avahi Apple Bonjour compatibility library  
ii libdns-export162     1:9.10.3.dfsg.p4-8ubuntu1.5 amd64   Exported DNS Shared Library  
ii libdns162:amd64      1:9.10.3.dfsg.p4-8ubuntu1.5 amd64   DNS Shared Library used by BIND  
ii libnss-mdns:amd64    0.10-7     amd64     NSS Module for Multicast DNS name resolution  

host -v www.apple.com

Trying "www.apple.com"  
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 1102  
;; flags: qr rd ra; QUERY: 1; ANSWER: 4; AUTHORITY: 0, ADDITIONAL: 0  

;;QUESTION SECTION:  
;www.apple.com.     IN      A  

;;ANSWER SECTION:  
www.apple.com.  1126    IN  CNAME   www.apple.com.edgekey.net.  
www.apple.com.edgekey.net.  21568   IN  CNAME   www.apple.com.edgekey.net.globalredir.akadns.net  
www.apple.com.edgekey.net.globalredir.akadns.net.   3599    IN  CNAME   e6858.dsce9.akamaiedge.net
e6858.dsce9.akamaiedge.net. 19  IN  A   172.226.108.101

Received 182 bytes from 8.8.8.8#53 in 152 ms  
Trying "e6858.dsce9.akamaiedge.net"  
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id:428  
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY:0, ADDITIONAL: 0  

;;QUESTION SECTION  
;e6858.dsce9.akamaiedge.net.    IN  AAAA  

;;ANSWER SECTION:  
e6858.dsce9.akamaiedge.net. 19  IN  AAAA    2001:559:19:988d::1aca  
e6858.dsce9.akamaiedge.net. 19  IN  AAAA    2001:559:19:988d::1aca  

Received 100 bytes from 8.8.8.8#53 in 70 ms  
Trying "e6858.dsce9.akamaiedge.net"  
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id:34978  
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY:1, ADDITIONAL: 0  

;;QUESTION SECTION:  
;e6858.dsce9.akamaiedge.net.    IN  MX  

;;AUTHORITY SECITON:  
dsce9.akamaiedge.net.   179 IN  SOA n0dsce9.akamaiedge.net.   hostmaster.akamai.com.    1490629947 1000 1000 1000 1800  

Received 109 bytes from 8.8.8.8#53 in 32 ms  

dpkg -l | grep libc6

ii libc6:amd64  2.23-0ubuntu7   amd64   GNU C Library: Shared Libraries  
ii libc6-dev:amd64  2.23-0ubuntu7   amd64   GNU C Library: Development Libraries and Header Files
  • Edit your question to include the terminal output of cat /etc/resolv.conf and cat /etc/NetworkManager/NetworkManager.conf and dpkg -l *dns* | grep ii and host -v www.apple.com. – heynnema Mar 27 '17 at 15:23
  • Please edit your answers into your original question by clicking "edit" under your question, and pasting in the output from terminal. Please don't use the comments to try and paste that info into. Thanks. – heynnema Mar 27 '17 at 15:30
  • Please paste also the output of dpkg -l | grep libc6 so we can see whether you are affected by the bug you mention. – fkraiem Mar 27 '17 at 16:30
  • Right, you have the latest version of libc6, so you are not affected by this bug. If libc6 was upgraded from the affected version, however, a reboot may be necessary. – fkraiem Mar 27 '17 at 16:50
  • That is good to hear! At least that helps narrow down why I have no DNS still. – dj1635 Mar 27 '17 at 18:21
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The file that stores information about what DNS servers to consult when resolving domain names is /etc/resolv.conf. But the problem with this file is that it is strongly advised not to edit that file by hand because if you do, it's soon going to be automatically overwritten by the resolvconf program. What you can do, however, is add the following lines to the /etc/resolvconf/resolv.conf.d/head file:

# Google's public DNS servers
nameserver 8.8.8.8    # Primary DNS server
nameserver 8.8.4.4    # Secondary DNS server

This file is used when constructing /etc/resolv.conf. Specifically, its contents are added to the beginning of the /etc/resolv.conf file.

  • I did what you instructed and if i ping a website or look at the host -v command, I get results with not packet loss. However, when I try to use a browser or try to do a apt-get update, the DNS fails. I think its related to the issue in the link above. Is there a way to get the IP of the Ubuntu update servers so I can run the update to fix the DNS bug? – dj1635 Mar 27 '17 at 13:14
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When the update will solve the problem it should not be too difficult to achieve that without DNS. Maybe a workaround is to find out out the IP address of your update server and enter that into your /etc/apt/sources.list instead of the fully qualified domain name.

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