Linux check which dns server

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.

2. Another way is to use the following grep command.

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

Easy 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.

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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:

sudo vi /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:

nmcli dev show | grep DNS

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

[Resolve]
DNS=8.8.8.8, 8.8.4.4

Как видите, все очень просто. Надеюсь, эта информация была вам полезной.

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3 Ways to check DNS records from Linux terminal

There are many third party websites that can verify a domain’s DNS records.

It can also be done from Linux terminal. Why not try yourself, instead of using 3rd party sites?

NIX users spend more time on terminal and looking for a viable option from the terminal for any purpose.

This will be useful not only for me, but also for others looking for a way to do their daily activities at the terminal.

Domain DNS information can be verified from the Linux terminal using the following three commands.

• host Command
• dig Command
• nslookup Command

Use one of the below command to verify domain owner information from the Linux terminal.

What’s Domain Name System (DNS)?

DNS stands for Domain Name System or Domain Name Servers which translates Internet domain and host names to IP addresses and vice versa.

DNS is a hierarchical decentralized naming system for computers, services, or other resources connected to the Internet or a private network.

It’s basically a set of mapping files that tell the DNS server which IP address each domain or host is associated with, and how to handle requests sent to each domain.

It stores various information about a domain & host such as A, AAAA, CNAME, MX, PTR, NS, SOA, SRV, TXT, and NAPTR.

A Record : A record stands for Address record. The ‘A’ record specifies the IP address (IPv4) of a host. Whenever DNS server get a query to resolve domain-name, it will refer the A record to answer the IP address.

AAA Record : The ‘AAA’ record specifies the IP address (IPv6) of a host.

NS Record : NS Record stands for Name Server record. NS Records maps a domain name to a list of authoritative DNS servers.

MX Record : MX Record stands for mail exchange record. MX Records maps a domain name to a list of mail exchange servers.

PTR Record : PTR record stands for Reverse lookup record or Pointer record. A PTR record maps the IP address to a specific host.

CNAME Record : CNAME Record stands for Canonical Name. CNAME record is used to create aliases that point to other names such as WWW, FTP, MAIL & subdomains to a domain name. Example : a CNAME record can associate the subdomain www.2daygeek.com with 2daygeek.com

SOA Record : SOA record stands for Start of Authority records. SOA records contain information about a DNS zone such as Primary nameserver, Hostmaster E-mail address, zone file seriel number, zone transfer interval and zone expiry details.

TXT Record : TXT Record stands for text record. A TXT record is a type of DNS record that provides text information to sources outside your domain. The text can be either human-or machine-readable and can be used for a variety of purposes.

SPF Record : SPF Record stands for Sender Policy Framework. SPF is an extension to the SMTP mail protocol which is used for e-mail authentication.

SPF record is used to verify whether the message came from an authorized mail server or not. SPF is designed to detect SPAM & PHISHING mail sender’s IP address which was included in the e-mail headers.

DKIM Record : DKIM record stands for Domain Keys Identified Mail. DKIM is an email validation system designed to detect email spoofing by providing encryption authentication to receiving mail exchangers.

It will check whether the incoming mail domain is authorized by the domain’s administrators and that the email (including attachments) has not been modified during transport.

A digital signature included with the message can be validated by the recipient using the signer’s public key published in the DNS.

1) How to verify a domain’s DNS records using the dig command

dig command stands for “domain information groper”. It is a flexible tool for interrogating DNS name servers. It performs DNS lookup and displays the answers that are returned from the name server(s) that were queried.

Most DNS administrators use dig to troubleshoot DNS problems because of its flexibility, ease of use and clarity of output. Other lookup tools tend to have less functionality than dig.

2) Checking DNS records of a domain using nslookup command

nslookup command is a program to query Internet domain name servers. Nslookup has two modes interactive and non-interactive.

Interactive mode allows the user to query name servers for information about various hosts and domains or to print a list of hosts in a domain.

Non-interactive mode is used to print just the name and requested information for a host or domain. It’s a network administration tool which will help them to check and troubleshoot DNS related issues.

3) How to check DNS records of a domain using host command

host command is a simple utility for performing DNS lookup. It is normally used to convert names to IP addresses and vice versa. When no arguments or options are given, host prints a short summary of its command line arguments and options as shown below:

Closing Notes

We have shown you three commands to find DNS records of a domain in Linux.

If you have any questions or feedback, feel free to comment below.

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Command-line to list DNS servers used by my system

Is there a command 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

11 Answers 11

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.

Ubuntu >= 15

Ubuntu is eth0 , which is common, but not always the case.

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.

In Ubuntu 18.04 and 20.04 you can use systemd-resolve —status

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

Or to see just the DNS do

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 :

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

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

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.

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How to Find Out What DNS Server Am I Using?

You have set up a new DNS server on your machine and you have no clue whether it’s working or not. Well, there are ways to check it. You can do it natively through the command line or with the help of third-party apps. Let me show you how.

Priority of DNS

Now, before we get to the process, it’s important to understand the priority of DNS servers. By default, we use the DNS servers provided by our ISP (Internet Service Provider). But what happens when you change the DNS server on your local machine or the router? Which DNS server gets the priority? Well, it’s easy.

If you change the DNS server on the router to let’s say Google DNS, then every device connected to the router will automatically start using Google DNS as the DNS Server. However, on top of that, if you change the DNS server on your local computer to let’s say Cloudflare DNS, then these settings will override the DNS settings of the router. Now, only your computer will use Cloudflare DNS while the rest of the devices will still use Google DNS.

So, if we rank the priority of DNS servers, it is going to be something like this,

1. If you’ve entered a custom DNS address on your computer or smartphone, that DNS server will be used
2. If you have not entered any custom DNS on your device, then the DNS server available on the router will be used
3. If you have not entered any custom DNS on your computer and router, then the DNS server provided by your ISP will be used.

If you want to read more about setting up DNS Server, you can read our detailed article on how to set up a DNS server.

1. What DNS Server Am I Using – Windows 10/8/7

If you have updated your DNS settings and the changes aren’t reflecting, try clearing your DNS cache or flush your DNS.

There are multiple ways to check the DNS Server on your Windows machine. Here is a couple of them.

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Method 1:

To check the DNS Server you are using on Windows, simply open up the command prompt. To do so on Windows 10, click on Start, then All Programs, then Accessories, and finally on Command prompt. and run the following command.

In case you are wondering, all that the command does is pulls all the network configuration values and then filter out the “DNS Servers” line from it.

Method 2:

The second method is much simpler and has a user-friendly command. That is, simply do a nslookup of any web address and Windows will show what DNS server you are using as part of the lookup. To do a nslookup, simply use the below command. You can replace “google.com” with any web address you want. In fact, you can even replace it with your own IP address.

2. What DNS Server Am I Using – Linux

To check what DNS server you are using on Linux, simply open up the terminal and do nslookup for any website. Just type in the following command. You can replace “google.com” with your own IP address as well.

In case you are wondering, “nslookup” is a command-line utility that resolves the DNS name to an IP address, thus revealing the DNS server used in the process.

3. What DNS Server Am I Using – Mac

Similarly, on macOS, open the terminal and type the following command.

To launch the terminal on macOS, press CMD + SPACE to launch Spotlight, and then type in ‘terminal’. and hit enter. Alternatively, you can open your Applications folder, then open Utilities, and double-click on Terminal. Once the terminal windows open, copy-paste the following command and hit enter.

4. What DNS Server Am I Using – Android

There are a handful of Android network scanner apps on the market that let you see what DNS you are using. I would suggest Network Info II. The app is ad-free and easy to use. Simply download it from the Google Play Store, open it, and go to the WiFi tab. There you’ll see DNS 1 and DNS 2 entries. These are the DNS servers you are using.

Alternatively, you can also try the PingTools Network Utilities. It does the basic job and also provides some additional utilities that can perform tasks like UPnP scanning, LAN wake-up, port scanning, etc.

To know the DNS address, install the app from Play Store and open it. Now, tap on the “Router” or “Internet” icon and it will display all the network details. Here, you can find what DNS you are using by looking at DNS 1 and DNS 2 entries.

5. What DNS Server Am I Using – iOS

Network Analyser is a free iOS app that shows useful information about your network. There is a premium version of this app that costs $3 but for our simple need, the lite version (ad-supported) is sufficient. Just install and open the app, you can see what DNS you are using next to “DNS Server IP.”

6. What DNS Server Am I Using – Router

By default, your router uses the DNS Server provided by your ISP. But if you suspect someone has changed it on your router, here’s how to find it. Simply open up the web browser, and type in the router’s IP address (usually 192.168.1.1 or192.168.0.1). In case you are not aware, here’s a quick way to check your router’s IP address. Next, log in with the username and password. Most of the routers have credentials written on the back.

Once you see the router’s web interface, depending on the router model look for DNS 1 and DNS 2 entries. Usually, it’s under the Network Setup or Status option.

In case you find any third-party DNS IP here, try googling the IP or do a nslookup with the IP to find out the server associated with it. If you are still unsure about the DNS service, then it is advisable to change the DNS on your local computer. This will override the setting on your Router and now you can peacefully enjoy browsing the web.

Closing Words

So, these were some of the ways to find out what DNS server you are using. Depending on the operating system you have, choose the most efficient way. You can also use online sites like WhatsMyDNSserver to quickly check your DNS service provider. However, the online method is slightly erroneous and wouldn’t provide you correct local DNS server IP.

In case you use third-party DNS providers like Cloudflare DNS or OpenDNS server, you can visit their sites to check your DNS server. For more issues or concerns, let me know in the comments below.

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