What DNS servers am I using?

Question

How can I check which DNS server am I using (in Linux)? I am using network manager and a wired connection to my university's LAN. (I am trying to find out why my domain doesn't get resolved)

The Linux kernel itself is not aware about DNS services. To answer it's better to know your userland. What distribution are you using? Ubuntu? Debian GNU/Linux? Centos? — Valerio Bozz, May 18 '21 at 07:49

score 316 · Accepted Answer · answered Jan 12 '12 at 12:38

316

You should be able to get some reasonable information in:

$ cat /etc/resolv.conf

answered Jan 12 '12 at 12:38

45

However, please be aware that (on modern Linuxen) the contents of /etc/nsswitch.conf dictate what name services are used (DNS, LDAP, etc) and in what order. Say fgrep hosts: /etc/nsswitch.conf. If it only references DNS, /etc/resolv.conf is the right place to look for your nameservers. But chances are you're also using mDNS (aka ZeroConf, aka Avahi, aka Bonjour, etc), etc. In that case, things depend on what you're using. – Alexios Jan 12 '12 at 13:35
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This file typically points at 127.0.1.1 on Ubuntu - it's the local DNS cache server, not the actual upstream. – Barry Kelly Mar 08 '16 at 10:24
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@BarryKelly Check what your router uses, then – Geremia Mar 11 '16 at 17:10
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And if you have several upstream server configured ? How to know which one is currently used ? – Sylvain Leroux Nov 24 '16 at 23:31
4

I would suggest to mention that file is a link and dynamically generated for systems using resovconf (like Ubuntu). I've seen this answer millions of times and until today is that I think it is correct, because I understand now that it is actually a dynamically generated file. – jgomo3 Dec 26 '17 at 18:00
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See the answers by @G32RW or @Lonniebiz for a more robust approach under various circumstances, e.g. when you get an answer like 127.0.0.53 – nealmcb Nov 11 '18 at 22:13
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@Geremia router? I'm on office wifi and I want to verify which DNS server I'm using. Or I'm on VPN and want to verify, similarly. Usually I don't have access to the router. – Barry Kelly Mar 20 '19 at 10:12
7

This solution is no more up to date. I find the systemd-resolve --status suggested by @G32RW most up-to-date solution for this problem. – Georgi Stoyanov Mar 27 '19 at 15:59
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There is no "systemd-resolve" in my Ubuntu 22.04 . Also "nmcli device show | grep -i dns" returns nothing. However, "resolvectl --protocol=dns | grep 'DNS Servers'" seems to work. – Marnix A. van Ammers Nov 25 '22 at 17:15
I would suggest adding: cat /run/systemd/resolve/resolv.conf to your answer if you are running a caching resolver on 127.X.X.X and actually want to know what's behind the cache. Or, as others have answered, you can also run resolvectl, or just resolvectl dns – B. Shea Mar 26 '24 at 18:09

score 305 · Answer 2 · edited Apr 01 '20 at 13:56

305

Here's how I do it:

( nmcli dev list || nmcli dev show ) 2>/dev/null | grep DNS

This worked previous to the way above:

nm-tool | grep DNS

On Debian, you need to have the network-manager package installed.

edited Apr 01 '20 at 13:56

Jeff Schaller

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answered May 30 '13 at 11:23

Lonnie Best

5,123

19

This one is usefull if you are using VPN and NetworkManager. Your /etc/resolv.conf will point to your machine, with dnsmasq resolving names as configured by NetworkManager. – Grzegorz Żur May 30 '13 at 11:32
7

On Debian this requires the network-manager package. – Neurotransmitter Feb 03 '15 at 19:44
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nm-tool is not available in newer linuxes. for example it is not in the 'network-manager' package of debian 8. – don bright Oct 31 '15 at 15:06
nm-tool | grep DNS No command 'nm-tool' found, did you mean: Command 'dm-tool' from package 'lightdm' (main) nm-tool: command not found – chovy Aug 31 '16 at 07:22
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I've updated the answer to reflect what's working for me in 2016. – Lonnie Best Sep 01 '16 at 16:36
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This did not work for me on an Ubuntu VM. nmcli dev show did not have the DNS info. However, systemd-resolve --status did have the real DNS server. https://unix.stackexchange.com/a/434756 – wisbucky Nov 14 '18 at 02:22
@wisbucky : That didn't work for me in 16.04, but people say its the new way in 18.04+. – Lonnie Best Nov 15 '18 at 00:29
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To add, you can also supply an interface name, e.g., nmcli dev show eth1 to show information about a specific adapter. Useful if you're troubleshooting a specific adapter that's connected differently than others. – Michael Stum Jun 30 '19 at 23:52
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nmcli is only installed for GUI distros, through network-manager package, not evailable in Ubuntu Server by default, for example – xCovelus Oct 03 '19 at 12:52
+1 for systemd-resolve --status as per https://unix.stackexchange.com/a/434756/36362 (as @wisbucky mentions above) on Ubuntu 18.04. – Johnny Utahh May 14 '20 at 18:38
What if I'm not using network manager? – Freeman May 18 '20 at 19:47
The question specifically indicates the use of Network Manager. If you're not using network manager, see other answers. – Lonnie Best Nov 18 '21 at 13:46

score 177 · Answer 3 · edited Jun 21 '21 at 00:56

177

On systems running systemd use:

systemd-resolve --status

Or:

resolvectl

edited Jun 21 '21 at 00:56

Brian Topping

103

answered Mar 31 '18 at 23:26

G32RW

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systemd-resolve: unrecognized option '--status' – Asclepius Apr 01 '18 at 18:03
@A-B-B system? systemd version? – G32RW Apr 01 '18 at 20:21
229-4ubuntu21.2 – Asclepius Apr 01 '18 at 23:34
18

Says Failed to get global data: Unit dbus-org.freedesktop.resolve1.service not found. – xji Apr 12 '18 at 11:19
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This is the new default way to do it in Ubuntu 18.04 Bionic Beaver - get used to it, everybody! – Avery Freeman Apr 24 '18 at 20:32
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This is the only solution that worked for me, as the others returned 127.0.0.53 – greuze Oct 25 '18 at 07:50
Not working on OpenSUSE Leap 15.1 – Megidd Oct 09 '19 at 13:28
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What am I reading? I only see DNSSEC records. – rosstex May 02 '20 at 16:22
Since the commands gives a lot of unrelated information, piping the output into grep DNS should return only DNS related information, including DNS servers currently in use. – Umlin Apr 30 '21 at 00:47
It says my DNS is 127.0.0.1, which is only the first entry in /etc/resolv.conf – kurdtpage Jul 06 '21 at 21:54
resolvectl is pretty verbose for me. resolvectl dns seems to give a nice, relatively compact list of DNS server IPs. – mwfearnley Sep 03 '21 at 09:14
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resolvctl worked for me in Ubuntu 22.04 . nmcli and systemd-resolve solutions did not work. – Marnix A. van Ammers Nov 25 '22 at 17:28

Freiheit · Answer 4 · 2019-04-02T13:04:56.763

111

I think you can also query DNS and it will show you what server returned the result. Try this:

dig yourserver.somedomain.xyz

And the response should tell you what server(s) returned the result. The output you're interested in will look something like this:

;; Query time: 91 msec
;; SERVER: 172.xxx.xxx.xxx#53(172.xxx.xxx.xxx)
;; WHEN: Tue Apr 02 09:03:41 EDT 2019
;; MSG SIZE  rcvd: 207

You can also tell dig to query a specific DNS server by using dig @server_ip

edited Apr 02 '19 at 13:04

answered Jan 12 '12 at 18:08

Freiheit

9,669

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On Debian this requires the dnsutils package. – Faheem Mitha Jan 14 '12 at 20:54
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If you use any DNS masking/caching service that is run on your local machine, it will hide the real DNS servers. – karatedog Sep 07 '15 at 09:12
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Ubuntu 18.04 just shows the local dns cache: SERVER: 127.0.0.53#53(127.0.0.53) – wisbucky Nov 14 '18 at 02:16
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This only tells you which server was used for that query. It doesn't tell you all the DNS servers that your host might use. – Marnix A. van Ammers Nov 28 '21 at 01:14
You can find all DNS servers used to satisfy a query by running dig +trace your.domain – vesperto Apr 11 '22 at 21:59
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Beware that this obviously fails if the DNS server is not available. That's not a common thing, but I've managed to get a bad result or timeout when looking for a DNS server running on IPv6 (using dig -6). – Maarten Bodewes Oct 27 '22 at 13:03

score 85 · Answer 5 · edited Jan 09 '17 at 11:44

85

Just do an, nslookup. Part of its results include the server that it's using.

In the example below, it shows that the DNS server used is at 8.8.8.8.

$ nslookup google.com
Server:     8.8.8.8
Address:    8.8.8.8#53

Non-authoritative answer:
Name:   google.com
Address: 172.217.22.174

edited Jan 09 '17 at 11:44

Mads Skjern

953

answered Feb 26 '15 at 02:45

Sam

859

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On Debian this requires the dnsutils package. – Gayan Weerakutti Aug 13 '17 at 07:00
22

On a recent Ubuntu, this again points to the local cache server 127.0.0.1 as already hinted at in this comment – FriendFX Dec 01 '17 at 01:50
In CentOS 7 it quits with error, but it is a vm so I did nslookup google.com in the Windows host and I found the nameserver. Add it in /etc/resolv.conf like: nameserver xx.xx.xx.xx and restart service network, and all is fine. Praise you. – WesternGun May 03 '18 at 15:22
Note that Nslookup is deprecated – Daniel Mar 13 '20 at 01:22
1

Didn't work: Server: 127.0.0.53, Address: 127.0.0.53#53 – Warren Parad May 26 '21 at 19:38

score 26 · Answer 6 · edited Dec 07 '20 at 21:59

26

With the new network-manager command nmcli, do this:

nmcli --fields ipv4.dns,ipv6.dns con show [connection_name]

On newer versions of network-manager (such as in Ubuntu 16.04), the field names are slightly different:

nmcli --fields ip4.dns,ip6.dns con show [connection_name]

If you don't know the connection name, use:

nmcli -t --fields NAME con show --active

For example, on old versions of nmcli :

$ nmcli --fields ip4.dns,ip6.dns con show 'Wired connection 1'
IP4.DNS[1]:                             172.21.0.13
IP4.DNS[2]:                             172.21.0.4

edited Dec 07 '20 at 21:59

Duncan Lock

145
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answered Nov 16 '15 at 01:28

Sameer

421

My results: order «con» «show» is not valid. – Sopalajo de Arrierez Jan 30 '16 at 22:03
It works fine for me with network-manager 1.0.4 on Ubuntu 15.10. Maybe you have an older version? – Sameer Mar 17 '16 at 05:40
The tabular format is pretty bad. I hope to get a column like format similar to Powershell. – CMCDragonkai Mar 14 '17 at 06:42
3

Returns Error: invalid field 'ip4.dns'; allowed fields: NAME,UUID,TYPE,TIMESTAMP,TIMESTAMP-REAL,AUTOCONNECT,AUTOCONNECT-PRIORITY,READONLY,DBUS-PATH,ACTIVE,DEVICE,STATE,ACTIVE-PATH. – FriendFX Dec 01 '17 at 01:53
simply nmcli was all i needed on ubuntu 19.04 – John Mee Oct 02 '19 at 05:54
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@FriendFX In newer versions of nmcli, the command is : nmcli --fields ip4.dns,ip6.dns dev show – SebMa Nov 19 '20 at 10:36
Ugh, as long as nmcli doesn't keep backwards compatibility with specific parameters and output format, I guess this is not a good way of testing for anything. – Maarten Bodewes Oct 27 '22 at 13:06

boly38 · Answer 7 · 2023-03-30T15:00:54.963

14

to get the first DNS SERVER (IP only) :

cat /etc/resolv.conf|grep -im 1 '^nameserver' |cut -d ' ' -f2

cat will output DNS config
grep filters only nameserver
-i grep ignore case
-m 1 grep stop after first match
cut take the ip part of the row (second column with ' ' as separator)

To put DNS ip in an environment variable, you could use as follow:

export THEDNSSERVER=$(cat /etc/resolv.conf|grep -im 1 '^nameserver' |cut -d ' ' -f2)

edited Mar 30 '23 at 15:00

answered Mar 27 '15 at 09:19

boly38

349

5

grep -m 1 stops matching after first match so you don't have to use head – sshow Jul 28 '17 at 08:30
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To lighten the pipeline even more, capture groups with Perl regexp is very neat, and grep takes a file argument: grep -Pom 1 '^nameserver \K\S+' /etc/resolv.conf. Just wrote up Capture groups with grep perl regular expression – sshow Jul 28 '17 at 09:04
There's both IPv4 and IPv6 DNS servers. Also, secondary servers exist for a reason. Which one this command returns? Is it advised to take the first one, and just ignore the others? – André Werlang Jan 16 '20 at 02:53

oHo · Answer 8 · 2022-09-26T17:25:22.393

13

Using `resolvectl`

$ resolvectl status | grep -1 'DNS Server'
    DNSSEC supported: no
  Current DNS Server: 1.1.1.1
         DNS Servers: 1.1.1.1
                      1.0.0.1

grep option: -C NUM, -NUM, --context=NUM Print NUM lines of output context.

For compatibility, systemd-resolve is a symbolic link to resolvectl on many distros as for Ubuntu 18.10:

$ type -a systemd-resolve
systemd-resolve is /usr/bin/systemd-resolve
$ ll /usr/bin/systemd-resolve
lrwxrwxrwx 1 root root 10 nov.  15 21:42 /usr/bin/systemd-resolve -> resolvectl
$ type -a resolvectl
resolvectl is /usr/bin/resolvectl
$ file /usr/bin/resolvectl
/usr/bin/resolvectl: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 3.2.0, BuildID[sha1]=09e488e849e3b988dd2ac93b024bbba18bb71814, stripped

edited Sep 26 '22 at 17:25

answered Dec 02 '18 at 14:13

oHo

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works perfect on Ubuntu 18.10. – Georgi Stoyanov Mar 27 '19 at 16:02
see also https://askubuntu.com/q/1149364/157358 about the name of the program – glS Jun 12 '21 at 11:38
1

As with other answers, thiis will simply return the caching service on your local host. – Maarten Bodewes Oct 27 '22 at 13:09

score 9 · Answer 9 · answered Jan 24 '12 at 05:30

If you are using network manager probably you get all network parameters from your dhcp server at your university.

If you don't want use your shell to check your dns settings (as described by hesse and Alexios), you can see them from the panel "Network information".

You can reach this panel by pressing right mouse button on network manager icon and selecting "Connection Information" from the menu.

score 6 · Answer 10 · edited Dec 18 '17 at 00:51

6

I have Fedora 25 and also had similar slow response on command line to sudo commands.

nmcli dev show | grep DNS

showed that only one of my 3 adapters (two active) had DNS entries. By adding DNS entries to the one active card that didn't have an entry - presto! All is good and response time is immediate.

edited Dec 18 '17 at 00:51

Jeff Schaller

67,283
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answered Dec 02 '17 at 22:29

CRTLBREAK

87

perhaps alternatively – Amos Folarin Jun 12 '19 at 17:44

score 4 · Answer 11 · edited May 18 '20 at 16:13

4

In Ubuntu >= 15

nmcli device show <interfacename> | grep IP4.DNS

Replace <interfacename> with yours.

In Ubuntu <= 14

The command

 nmcli dev list iface <interfacename> | grep IP4

Replace <interfacename> with yours.

Examples

 nmcli device show eth0 | grep IP4.DNS

Or

 nmcli dev list iface eth0 | grep IP4

This will list all DNS servers(If you use more than one).

edited May 18 '20 at 16:13

loved.by.Jesus

431

answered Mar 27 '15 at 09:44

Maythux

1,888

score 3 · Answer 12 · answered Dec 25 '20 at 14:38

On a recent Fedora 33, you can just use

# resolvectl dns
Global:
Link 2 (enp0s31f6):
Link 3 (wlp4s0): 1.1.1.1 8.8.8.8
Link 4 (virbr0):
Link 5 (virbr0-nic):

To check if systemd-resolved is active, do cat /etc/resolv.conf It will tell you who is controlling the file.

If you want more details, you can use resolvectl status resolvectl statistics, you can also flush caches ...

To troubleshoot, you can use journalctl -u systemd-resolved -f -o cat | grep Looking after setting the level to DEBUG: sudo resolvectl log-level debug

Only returns local caching DNS, i.e. localhost. – Maarten Bodewes Oct 27 '22 at 13:11 — Maarten Bodewes, Oct 27 '22 at 13:11

SebMa · Answer 13 · 2020-12-26T08:25:59.700

1

On systems where systemd-resolved is NOT installed :

$ host -v something.unknown | awk -F "[ #]" '/Received /{print$5}' | uniq
192.168.1.1

On systems where NetworkManager is running :

$ ( nmcli -f IP4.DNS,IP6.DNS dev list || nmcli -f IP4.DNS,IP6.DNS dev show ) 2>/dev/null | awk '/DNS/{print$NF}'
192.168.1.1

edited Dec 26 '20 at 08:25

answered Apr 01 '20 at 12:30

SebMa

2,149

score 0 · Answer 14 · answered Nov 27 '17 at 05:32

0

In CentOS, you can use:

/usr/sbin/named -v

answered Nov 27 '17 at 05:32

Miloud Eloumri

101

What DNS servers am I using?

14 Answers14

Using `resolvectl`

In Ubuntu >= 15

In Ubuntu <= 14

Examples

Linked

Related

What DNS servers am I using?

14 Answers14

Using resolvectl

In Ubuntu >= 15

In Ubuntu <= 14

Examples

Linked

Related

Using `resolvectl`