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
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
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