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I have an Ubuntu 14.04 host and have a 15.10 server running in virtualbox. This is all a fresh install that I completed 3 days ago.

When I logged in last night to run "apt-get update", nothing resolved.

I'm attempting to use my router as the DNS server server. That's how I have the rest of my LAN setup. I can resolve successfully from the host, but I cannot resolve anything from the guest.

 source /etc/network/interfaces.d/*

 # The loopback network interface
 auto lo
 iface lo inet loopback

 # The primary network interface
 auto enp0s3
 iface enp0s3 inet static
    address 192.168.1.4
    netmask 255.255.255.0
    network 192.168.1.0
    gateway 192.168.1.1
    dns-namesevers 192.168.1.1

I can ping my router. If I change the dns-nameservers to 8.8.8.8 and restart networking, I still can't resolve google.com. There's something on the box that's preventing DNS queries from resolving and I'm not sure what could cause it. Thanks for the help.

  • Any firewall/iptable rules? Just in case? Can you tell us result of "telnet 192.168.1.1 53" from your guest system and also from your supervisor system? Just for a starter. – Jacek Jan 13 '16 at 16:14
  • Also - are you absolutely sure, that your supervisor system is also using 192.168.1.1 as DNS? Is DNS working fine on that IP, for sure? – Jacek Jan 13 '16 at 16:16
  • I personally did not setup any firewall/iptable rules. In fact, I have to lookup how to check that to confirm. I wouldn't even know how to enter them to begin with. When I telnet to the router it says it's connected. I can't interact with it at all, it just goes to the next line when I send a command. Same from host system as well. Yes, the host is using 192.168.1.1 as DNS. When I do a dig though, it's querying itself (127.0.0.1) – LineNoise Jan 13 '16 at 23:40
  • 'linenoise@servermoo:~$ sudo iptables -L [sudo] password for linenoise: Chain INPUT (policy ACCEPT) target prot opt source destination Chain FORWARD (policy ACCEPT) target prot opt source destination Chain OUTPUT (policy ACCEPT) target prot opt source destination linenoise@servermoo:~$' (all blank, that did not copy gracefully at all and I can't get the 'code' tag to work here) – LineNoise Jan 13 '16 at 23:45
  • Well - to be honest, if you say telnet to port 53 works from both host/hypervisor and guest - maybe there's something in the configuration that makes dns not respond to the guest with the proper answer. I'm afraid that I can be only guessing here. You have to check things carefully on your system. – Jacek Jan 14 '16 at 9:02
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the same thing going on here I think it is something related to DNSMASQ some times dns resolution never works ,some times it works slowly taking for each name about 3 seconds to resolv ,and sometimes it runs really fast as it should be . I'm running ubuntu 15.10 and yes I tried to change dns servers to my ISP,Goolge,and opendns nothing seems to be stable

UPDATE: I think I found the solution

SOLUTION

The problem seems to be related to the conflicting dnsmasq and resolvconf packages. Until 12.10, dnsmasq was used. From 13.04 onwards, Ubuntu seemed to switch to a dnsmasq/resolvconf hybrid, where you have installed the packages dnsmasq-base and resolvconf, but not dnsmasq itself.

I can't say if it's a bug in the upgrade scripts for 13.04 or something else, because when upgrading (as in fresh installs) resolvconf is installed, dnsmasq-base is upgraded and dnsmasq is (correctly) uninstalled.

The catch is, the upgrade script fails to comment out the dns=dnsmasq line in /etc/NetworkManager/NetworkManager.conf. So, even though the dnsmasq daemon is not present anymore on the system, /etc/resolv.conf still expects it to be.

SO to fix the problem edit this file /etc/NetworkManager/NetworkManager.conf and comment this line : #dns=dnsmasq

hope this helps some one

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