23

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
1

4 Answers 4

Reset to default
18

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
4
  • 1
    My Ubuntu 16 system wants nmcli dev show
    – nortally
    Commented Apr 6, 2016 at 23:14
  • That's because nmcli version has been changed in since Ubuntu 15.04 due to transition to different init system, so yes, in newer releases the command is just slightly different
    – Sergiy Kolodyazhnyy
    Commented Nov 28, 2016 at 19:42
  • When I'm logged in to my work network using NetworkManager and VPNC, I don't see my work's DNS server in this output, even though clearly it is resolving. I don't (yet) know how to see the VPN DNS server.
    – Peter V. Mørch
    Commented Jan 26, 2017 at 16:56
  • 1
    To make dnsmasq show the DNS that it's using, one can send it the USR1 signal and it'll then dump stats and such to syslog. So, do: tail -F /var/log/syslog | grep dnsmasq.\*Server & sudo pkill -USR1 dnsmasq
    – alexs77
    Commented Mar 14, 2017 at 12:44
17

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.

7
  • @jdthood - your changes are quite extensive and could be construed to go beyond the OP's intent. Please create your own answer if required to support your thoughts. Thanks.
    – fossfreedom ♦
    Commented Mar 26, 2013 at 13:54
  • @jdthood: I do appreciate your effort to ensure a correct answer. It is however my understanding that the default behavior of dnsmasq, as integrated with NetworkManager, is to cache 150 entries in accordance with their respective TTL settings.
    – Roy
    Commented Mar 26, 2013 at 13:58
  • By default NM-dnsmasq's cache is disabled. Do ps -ef|grep dnsmasq and look for the option --cache-size=0.
    – jdthood
    Commented Mar 26, 2013 at 14:17
  • 1
    That's not the case on my 12.04 box, but a google search shows that you are right, that is the default on both 12.04 and 12.10. So, a caching DNS server with caching disabled then :)
    – Roy
    Commented Mar 26, 2013 at 15:49
  • dnsmasq appears to be using the closest dns server(i.e., the one it can reach fastest), if you specify two or more in your settings. Which makes sense from (providing faster) user experience point of view. Plus, the resolv.conf file mentioned the other, OpenDNS as fallback, not primary, right ?
    – Sergiy Kolodyazhnyy
    Commented Jan 6, 2015 at 11:37
7

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)

2
  • Great! It will help me when the DNS disappears...
    – karatedog
    Commented Sep 4, 2015 at 10:21
  • 1
    nmcli device show wlan0 in my case
    – Searene
    Commented Oct 7, 2015 at 2:23
1

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

0

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .