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 How to Find My DNS Server IP Address in Linux
DNS (Domain Name System) is a fundamental facilitator of several networking technologies such as mail servers, Internet browsing, and streaming services e.g. Netflix and Spotify, among others.
It works on a special computer called a DNS server – which keeps a database record of several public IP addresses along with their corresponding hostnames in order for it to resolve or translate hostnames to IP addresses upon user request.
This happens so that we would not need to bother ourselves with remembering the IP addresses of the different websites we visit.
While there are several things we can discuss on DNS servers such as redirection and malware attack prevention, our focus today is on how to find out your very own dns server IP address.
There are several ways to check for it depending on the Operating System that you’re running but Linux, BSD, and Unix-like systems all share the same method so let’s begin with them.
How to Find My DNS Server IP Address
1. To find out your DNS Server IP address, use the following cat command or less command.
$ cat /etc/resolv.conf OR $ less /etc/resolv.conf
2. Another way is to use the following grep command.
$ grep "nameserver" /etc/resolv.conf nameserver 109.78.164.20
Here, nameserver 109.78.164.20 is a name server IP address in what is called the dot notation – the format that applications on your workstation use for DNS routing.
How to Find My Website DNS Server IP Address
3. To find out a website DNS Server IP address, you can use the following dig command.
Sample Output
; > DiG 9.8.2rc1-RedHat-9.8.2-0.68.rc1.el6_10.1 > tecmint.com ;; global options: +cmd ;; Got answer: ;; ->>HEADEREasy right? Perhaps we’ll talk about primary and secondary DNS Server addresses next time. Till then, feel free to share and drop your comments/suggestions in the discussion section below.
Как посмотреть DNS в Linux
Служба DNS или Domain Name System позволяет превращать легко читаемый адрес сайта в ip адрес сервера на котором расположен этот сайт. Для этого используются DNS серверы, которые содержат таблицы соответствия ip адресов их доменным именам. По умолчанию система получает адрес DNS сервера автоматически по DHCP при подключении к сети.
В этой статье мы разберемся как посмотреть какие DNS серверы используются в Linux.
Как посмотреть DNS в Linux
Если вы уже имели опыт настройки сети в Linux, то знаете, что DNS серверы, используемые для резолвинга доменных имен указаны в файле /etc/resolv.conf:
Но в современных дистрибутивах Linux с системой инициализации systemd обычно запущен локальный DNS сервер, адрес которого и прописан в этом файле, а какие сервера используются на самом деле непонятно. В таком случае можно воспользоваться утилитой systemd-resolve:
В самом низу вывода утилиты можно посмотреть DNS в Linux, которые сейчас используются. Информация выводится по каждому сетевому интерфейсу отдельно.
Также для решения подобной задачи можно использовать утилиту nmcli:
Как видите, все очень просто. А чтобы изменить DNS сервер тоже трогать /etc/resolv.conf не желательно, так как он будет автоматически обновляться после перезагрузки. Если вы используете NetworkManager, то можно настроить DNS для сетевого подключения в интерфейсе программы. Или же можно отредактировать файл /etc/systemd/resolved.conf и добавить нужные адреса в секцию Resolve:
sudo vi /etc/systemd/resolved.conf
Как видите, все очень просто. Надеюсь, эта информация была вам полезной.
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