Master nslookup on Linux: Install and 7 Essential Commands

Installation on Debian/Ubuntu

Use the apt package manager to install the dnsutils package, which provides the nslookup command.

sudo apt update
sudo apt install dnsutils

Installation on CentOS/RHEL

Use yum or dnf to install the bind-utils package, which includes nslookup. Choose the command that matches your system version.

# For yum‑based systems
sudo yum install bind-utils

# For dnf‑based systems
sudo dnf install bind-utils

Usage 1: Query an IP address

Run nslookup followed by a domain name to retrieve its IPv4 address.

nslookup example.com

Usage 2: Specify a DNS server

You can direct the query to a particular DNS server instead of the default local resolver.

nslookup example.com 8.8.8.8

Usage 3: Query a specific DNS record type

Use the -type option to request records other than the default A record, such as MX (mail exchange) records.

nslookup -type=MX example.com

Usage 4: Perform a reverse lookup

Provide an IP address to retrieve the associated domain name.

nslookup 1.1.1.1

Usage 5: Set a search domain

When querying, you can define a search domain to automatically append to unqualified hostnames.

nslookup -d2 example.com

Usage 6: Use the set command

Inside the interactive nslookup prompt, the set command lets you modify options such as query type or timeout.

nslookup
set type=A
example.com

Usage 7: Exit the interactive mode

In interactive mode, type exit or quit to leave nslookup.

exit

The nslookup tool is useful for diagnosing DNS problems such as failed name resolution, stale caches, or misconfigurations, but keep in mind that results may be affected by local DNS cache settings or the configuration of the queried DNS server.