Master nslookup on Linux: Install, Query, and Advanced Usage Guide

nslookup is a network diagnostic tool used to query DNS records, converting domain names to IP addresses or retrieving other record types such as MX or CNAME.

Debian/Ubuntu and derivatives installation

Install via apt:

<code>sudo apt update
sudo apt install dnsutils</code>

The dnsutils package includes the nslookup command.

CentOS/RHEL and derivatives installation

Install via yum or dnf depending on the system version:

<code># For yum‑based systems
sudo yum install bind-utils

# Or for dnf‑based systems
sudo dnf install bind-utils</code>

The bind-utils package contains the nslookup command.

Usage 1: Query IP address

Run nslookup with the domain name to obtain its IP address.

<code>nslookup example.com</code>

Usage 2: Specify DNS server

Specify a DNS server for the query instead of the default.

<code>nslookup example.com 8.8.8.8</code>

Usage 3: Query specific DNS record type

Use nslookup to query record types other than A, such as MX.

<code>nslookup -type=MX example.com</code>

Usage 4: Reverse lookup

Perform a reverse lookup to find the domain name associated with an IP address.

<code>nslookup 1.1.1.1</code>

Usage 5: Set search domain

When using nslookup, you can set a search domain to specify the domain to be searched.

<code>nslookup -d2 example.com</code>

Usage 6: Use set command

nslookup provides an interactive mode where the

set

command can change query options such as timeout or query type.

<code>nslookup
set type=A
example.com</code>

Usage 7: Exit nslookup

In interactive mode, exit with the

exit

or

quit

command.

<code>exit</code>

Using nslookup helps diagnose DNS problems such as resolution failures, cache issues, or configuration errors, but results may be affected by local DNS cache or server settings.