nslookup and dig for DNS in Linux CLI - Commands & Configuration

Introduction

Sometimes you need to find the address of a website or check if a domain name is working correctly. nslookup and dig are tools that help you ask the internet's phone book, called DNS, to find this information for you.

When you want to find the IP address of a website like example.com

When you need to check if your domain name is pointing to the right server

When troubleshooting internet connection problems related to domain names

When you want to see detailed information about DNS records for a domain

When you want to verify if DNS changes have been updated properly

Commands

This command asks the DNS to find the IP address for example.com using nslookup.

Terminal

nslookup example.com

Expected Output

Server:  192.168.1.1

Address: 192.168.1.1#53



Non-authoritative answer:

Name:    example.com

Address: 93.184.216.34

This command uses dig to get detailed DNS information about example.com, including its IP address.

Terminal

dig example.com

Expected Output

; <<>> DiG 9.16.1-Ubuntu <<>> example.com

;; global options: +cmd

;; Got answer:

;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 12345

;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1



;; QUESTION SECTION:

;example.com.                   IN      A



;; ANSWER SECTION:

example.com.            3600    IN      A       93.184.216.34



;; Query time: 20 msec

;; SERVER: 192.168.1.1#53(192.168.1.1)

;; WHEN: Fri Jun 14 12:00:00 UTC 2024

;; MSG SIZE  rcvd: 56

This command asks dig to show the mail servers (MX records) for example.com, which handle email for the domain.

Terminal

dig example.com MX

Expected Output

; <<>> DiG 9.16.1-Ubuntu <<>> example.com MX

;; global options: +cmd

;; Got answer:

;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 12346

;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1



;; QUESTION SECTION:

;example.com.                   IN      MX



;; Query time: 15 msec

;; SERVER: 192.168.1.1#53(192.168.1.1)

;; WHEN: Fri Jun 14 12:01:00 UTC 2024

;; MSG SIZE  rcvd: 43

Key Concept

If you remember nothing else, remember: nslookup is simple for quick lookups, while dig gives detailed DNS info for deeper troubleshooting.

Common Mistakes

Typing only 'nslookup' or 'dig' without a domain name

The tools need a domain name to look up; without it, they wait for input or show help, which is not useful.

Always include the domain name you want to check, like 'nslookup example.com' or 'dig example.com'.

Expecting dig output to be short and simple like nslookup

dig shows a lot of technical details which can be confusing if you only want the IP address.

Use dig when you want detailed info; for quick IP lookups, nslookup is easier.

Summary

Use nslookup to quickly find the IP address of a domain.

Use dig to get detailed DNS records and troubleshoot DNS issues.

Always specify the domain name when running nslookup or dig commands.