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Martin Thoma
Asked: 2013-03-21 09:12:12 +0800 CST

What is my DNS server?

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My /etc/resolv.conf looks like this:

# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
#     DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
nameserver 127.0.1.1

# OpenDNS Fallback (configured by Linux Mint in /etc/resolvconf/resolv.conf.d/tail).
nameserver 208.67.222.222
nameserver 208.67.220.220

When I use nslookup, I seem to use 127.0.1.1:

moose@pc08 ~ $ nslookup www.google.com
Server:     127.0.1.1
Address:    127.0.1.1#53

Non-authoritative answer:
Name:   www.google.com
Address: 173.194.44.17
Name:   www.google.com
Address: 173.194.44.16
Name:   www.google.com
Address: 173.194.44.19
Name:   www.google.com
Address: 173.194.44.18
Name:   www.google.com
Address: 173.194.44.20

But when I right-click on network manager and click on "connection information" I get:

connection information

whois 217.0.43.129 reveals that this belongs to Deutsche Telekom AG, my ISP.

Why does network manager show this information? What DNS server am I currently using?

dnsmasq

Yes, I seem to run dnsmasq:

moose@pc08 ~ $ ps aux | grep dnsmasq
nobody    1479  0.0  0.0   5468  1404 ?        S    14:16   0:00 /usr/sbin/dnsmasq --no-resolv --keep-in-foreground --no-hosts --bind-interfaces --pid-file=/var/run/sendsigs.omit.d/network-manager.dnsmasq.pid --listen-address=127.0.1.1 --conf-file=/var/run/nm-dns-dnsmasq.conf --cache-size=0 --proxy-dnssec --enable-dbus=org.freedesktop.NetworkManager.dnsmasq --conf-dir=/etc/NetworkManager/dnsmasq.d
network-manager

4 Answers

  1. As en expansion of happyskeptic's answer, you don't need to specify an interface. This does it for me:

    > nmcli dev show | grep DNS
IP4.DNS[1]:                             172.22.216.251
IP6.DNS[1]:                             2a01:4f0:400c:1::1

    For Ubuntu 14.04 and older use nmcli dev list | grep DNS

    > nmcli dev list | grep DNS
IP4.DNS[1]:                             172.22.216.251
IP6.DNS[1]:                             2a01:4f0:400c:1::1
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  2. Best Answer

    You are using dnsmasq, a lightweight forwarding DNS server that runs locally under the control of NetworkManager. Dnsmasq forwards DNS queries to the DNS servers whose addresses have been provided by the DHCP server. It is also possible to set these DNS server addresses statically using the Connection Editor.

    The dnsmasq executable is provided by the dnsmasq-base package on which the network-manager package depends. There is also a package called simply "dnsmasq" which also depends on dnsmasq-base, but this "dnsmasq" package should only be installed if you want to run dnsmasq independently of NetworkManager in order to take advantage of features other than mere DNS forwarding.

    • 17

  3. I've found that on Kubuntu 14.04 the NetworkManager applet (or Plasma thing, whatever it's called) in KDE doesn't show the DNS server info under the connection details.

    In this case the way to find it is to run the following at the command line and look for the lines 'IP4.DNS':

    nmcli dev list iface wlan0

    (replace wlan0 with the interface you use to connect to the Net)

    • 7

  4. You're using the 217.0.43.129. if both your primary and secondary DNS are not found, it'll go to your router and use the DNS server configured in the router. If that DNS fails as well, it'll probabely try to connect to the openDNS server. as configured in /etc/resolv.conf.

    https://lists.isc.org/pipermail/bind-users/2006-October/064570.html

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