Check dns servers linux

What DNS servers am I using?

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?

14 Answers 14

You should be able to get some reasonable information in:

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.

This file typically points at 127.0.1.1 on Ubuntu — it’s the local DNS cache server, not the actual upstream.

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

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.

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

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

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.

nm-tool is not available in newer linuxes. for example it is not in the ‘network-manager’ package of debian 8.

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. unix.stackexchange.com/a/434756

On systems running systemd use:

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

If you use any DNS masking/caching service that is run on your local machine, it will hide the real DNS servers.

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.

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 ).

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 

On a recent Ubuntu, this again points to the local cache server 127.0.0.1 as already hinted at in this comment

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.

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 

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.

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) 

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

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?

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 

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3 Ways to check DNS server IP in Linux

DNS servers are an important part of the internet, translating domain names into IP addresses. If your DNS server is not working correctly, you may experience problems loading websites or sending and receiving email. In this blog post, we will discuss three ways to check your DNS server in Linux. We will also provide some tips for troubleshooting DNS problems. Let’s get started!

Check DNS server IP with Dig command in Linux

The best way to check your DNS server is to use the ‘dig’ command. The ‘dig’ command allows you to query DNS servers for information about domains. To use the ‘dig’ command, open a terminal and type the following: dig example.com

This will query the DNS server for information about the domain “example.com”. For example, if you want to query for A records, you would type the following: dig example.com +short

You can replace “example.com” with any domain you want to query. From the following example, we can see that the DNS server is 64.104.76.247 .

dig howtouselinux.com
; > DiG 9.10.6 > howtouselinux.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER ;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1280
;; QUESTION SECTION:
;howtouselinux.com. IN A
;; ANSWER SECTION:
howtouselinux.com. 0 IN A 162.159.137.9
howtouselinux.com. 0 IN A 162.159.138.9
;; Query time: 138 msec
;; SERVER: 64.104.76.247#53(64.104.76.247)
;; WHEN: Wed Mar 02 21:24:01 CST 2022
;; MSG SIZE rcvd: 78

Check DNS server IP with nslookup command in Linux

The second way to check your DNS server is to use the ‘nslookup’ command. ‘Nslookup’ is a tool that allows you to query DNS servers for information about domains. To use the ‘nslookup’ command, open a terminal and type the following: nslookup example.com

This will query the DNS server for information about the domain “example.com”. You can also query specific records by using the ‘querytype’ parameter. For example, if you want to query for A records, you would type the following: nslookup -query=a example.com

The dns server is 64.104.76.247 from the following example.
% nslookup -query=a howtouselinux.com
Server: 64.104.76.247
Address: 64.104.76.247#53
Non-authoritative answer:
Name: howtouselinux.com
Address: 162.159.137.9
Name: howtouselinux.com
Address: 162.159.138.9

Check DNS server IP with /etc/resolv.conf file in Linux

The third way is to check /etc/resolv.conf configuration file. It contains DNS server information we use.

cat /etc/resolv.conf
domain howtouselinux.com
nameserver 64.104.76.247
nameserver 64.104.76.248

We hope this blog post has been helpful in showing you how to check your DNS server in Linux. If you are experiencing DNS problems, be sure to try using these three commands to troubleshoot the issue. Thanks for reading!

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Command-line to list DNS servers used by my system

But it doesn’t list any servers, if I go to «Network Manager GUI Tool», in Wireless section it lists «DNS 192.168.1.1 8.8.8.8 8.8.4.4» Can I get same information from command line? I am using Ubuntu 12.04 LTS

What are you trying to find? the DNS servers being used by your system? or are you trying to do a DNS lookup?

13 Answers 13

resolv.conf isn’t really used anymore, unless you implement it yourself. The network manager does it now. I created an alias to list the DNS servers on my system, as I sometimes switch from OpenDNS to Google’s open DNS.

nmcli device show | grep IP4.DNS 

nmcli dev list iface | grep IP4 

In my case, is eth0 , which is common, but not always the case. You can see your interfaces with

See if this is what you want.

I think resolv.conf is actually used indirectly, because the network manager creates the server that listens on 127.0.0.1, but I was told that this is an implementation detail that should not be counted on. I think that if you enter DNS addresses before this entry, they might get used, but I’m not sure exactly how this works. I think it’s best to use the network manager in most cases, when possible.

thanks, yes that seems to be working, ubuntu networking seems to be confusing, so I can set dns servers in resolve.conf/base or in /etc/network/interfaces or in network manager, is there a definitive guide for ubuntu networking?

@vcardillo: the original question stated: «I am using Ubuntu 12.04 LTS». It’s been 5 years since I posted my answer. Nothing lasts forever.

I would like to warn readers that the information provided by nmcli and nm-tool might not be correct. In testing my router setup, I changed the DHCP server to configure a DNS. On my client (linux mint 17.3) I did sudo dhclient -r; sudo dhclient to renew IP configuration. At this point both commands I mentioned showed the old DNS, not the new one. cat /etc/resolv.conf did work for me, but according to op it did not work for him. The only reliable way to figure out which DNS is used appears to be to a lookup with for example dig, but I doubt dig will show you all configured DNS.

In Ubuntu 18.04 and 20.04 you can use systemd-resolve —status . In newer versions use resolvectl status .

IMO this should be the accepted answer. Also, it’s worth pointing out that systemd-resolve mydomain.com outputs which DNS server exactly is being queried (very useful if e.g. you have set up a VPN and so on).

This is valid for Ubuntu 13.10 and earlier. For Ubuntu 14.04 and above, see Koala Yeung’s answer to: How to know what DNS am I using in Ubuntu from 14.04 onwards

You will get an output similar to

NetworkManager Tool State: connected (global) - Device: eth0 [Wired connection 1] ------------------------------------------- Type: Wired Driver: e1000e State: connected Default: yes HW Address: 00:11:22:33:44:55 Capabilities: Carrier Detect: yes Speed: 1000 Mb/s Wired Properties Carrier: on IPv4 Settings: Address: 10.21.6.13 Prefix: 24 (255.255.255.0) Gateway: 10.21.6.1 DNS: 10.22.5.133 DNS: 10.22.5.3 

Or to see just the DNS do

yeah this doesn’t work anymore. no nm-tool in 16.x either. nmcli (in Marty Fried’s answer) is the way to go

The two top-scoring answers, nmcli dev list iface | grep IP4 and nm-tool both assume that network-manager is in control. Which it is — on desktop machines most of the time at least. But the fuller answer is that sometimes network-manager is not in control. E.g. vpnc messes with /etc/resolv.conf directly.

So: First check if 127.0.0.1/localhost is used. This could be done with dig :

> dig something.unknown | grep SERVER: ;; SERVER: 127.0.0.1#53(127.0.0.1) 

Now you know that we are using localhost. Go ahead with one of the popular answers. I like:

> nm-tool | grep DNS: DNS: 8.8.8.8 

But if 127.0.0.1/localhost is not used, then nm-tool ‘s and nmcli ‘s output will be misleading:

> dig something.unknown | grep SERVER: ;; SERVER: 172.22.216.251#53(172.22.216.251) > nm-tool | grep DNS: DNS: 8.8.8.8 

Here, dig is correct and nm-tool ‘s information is misleading. In reality addresses local to the environment I’ve VPN-ed into are resolved correctly. All of which Google’s DNS 8.8.8.8 doesn’t know about.

This is because after connecting to a VPN with vpnc , it puts a line in /etc/resolv.conf so it looks like:

# 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 1.2.3.4 nameserver 127.0.0.1 search MyDomain 

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