I'm running mint Mate 17.2.

When I use dig, for a certain specific domain name, the resolved IP "answer" is wrong, and the answer server is

Trying to access this domain from my local computer via ssh, a web browser, etc also resolves to the wrong IP.

DNS lookup using online tools or other computers works correctly.

Something on the local machine is intercepting the request and returning a wrong cached result. I have looked at various caching programs, but I don't think I have any installed or configured any.

The IP address being returned is the old IP and the master DNS records were changed over a year ago.

How do I determine what program is intercepting DNS locally and disable it so I can have this domain resolve correctly on my computer?


# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
  • Add the contents of /etc/resolv.conf. Also, are you certain that you're not running a local DNS server such as bind?
    – DopeGhoti
    May 29 '16 at 5:28
  • I added resolv.conf above. bind or bind9 is not in /etc/init.d so I assume it's not installed.
    – Nick
    May 29 '16 at 7:00
  • @DopeGhoti must be resolvconf or dnsmasq. May 29 '16 at 7:01
  • resolvconf is in init.d. dnsmasq is not installed. Still not sure where resolvconf is getting it's info from though, since there's nothing set in resolv.conf or /etc/hosts.
    – Nick
    May 29 '16 at 7:12
  • 1
    what is the output of sudo netstat -anlp | grep :53? May 29 '16 at 7:13

Resolvconf is pointing it out to a local software running in port 53 in the local machine.

To find it out which one:

sudo netstat -anlp | grep :53

As we have found out, it is the avahi daemon.

To trace DNS resolution, also following command is useful:

dig +trace www.cnn.com

If you want to control your DNS setting yourself, specially in server cases (I have notice you said Mint), I would recommend doing away with resolvconf

You can uninstall it with:

dpkg --purge resolvconf

Then, if you got the IP via DHCP leave it as it is, otherwise fill in your DNS servers in /etc/resolv.conf.

If you are not also interested in mDNS resolution or in a corporate network, I recommend uninstalling avahi.

In desktop settings, it maybe advisable either to reboot or restart all services. I would at least restart networking with service networking restart.

The Avahi mDNS/DNS-SD daemon implements Apple's Zeroconf architecture (also known as "Rendezvous" or "Bonjour"). The daemon registers local IP addresses and static services using mDNS/DNS-SD and provides two IPC APIs for local programs to make use of the mDNS record cache the avahi-daemon maintains.

In a work setting, it maybe also be interesting following up at the network level servers/workstations which are announcing mDNS records, and if they are strictly necessary. I would bet some lost host file or some old server setting is propagating your old IP address via mDNS.

You may also listen in the local network mDNS packets with:

sudo tcpdump -n udp port 5353

From mDNS

The multicast Domain Name System (mDNS) resolves host names to IP addresses within small networks that do not include a local name server. It is a zero-configuration service, using essentially the same programming interfaces, packet formats and operating semantics as the unicast Domain Name System (DNS). Although Stuart Cheshire designed mDNS to be stand-alone capable, it can work in concert with unicast DNS servers.

  • 2
    Thanks for your help. The erroneous entry was coming from the router which has it's own DNS server built in. Once I disabled resolvconf on my computer, dig showed the router's IP, not the loopback IP as the source of the bad records. It's a shame resolvconf hides the true source of the records from dig.
    – Nick
    May 29 '16 at 8:04
  • I do not allow neither resolvconf nor avahi services in my servers at work and my Linux router at home. Usually soho router DNS services are slow...better have a dedicated Linux DNS server/cache. May 29 '16 at 8:12
  • As for the router, the old entry was put there by hand, right? May 29 '16 at 13:03
  • 1
    Yes, it was manually added a long time ago.
    – Nick
    May 29 '16 at 14:34
  • But with Ubuntu/Mint, dpkg --purge resolvconf tells you ubuntu-minimal depends on resolvconf.
    – einpoklum
    Mar 9 '17 at 21:13

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.