Linux nslookup Command with Examples

The nslookup command is a useful Linux networking utility for querying the Domain Name System (DNS). DNS translates human-readable domain names such as www.example.com into IP addresses that computers use to communicate over a network. The nslookup command allows students, system administrators, developers, and testers to examine DNS information and troubleshoot name-resolution problems.

What is nslookup?

nslookup stands for Name Server Lookup. It sends DNS queries to a configured DNS server and displays the response. It can be used to find IPv4 addresses, IPv6 addresses, mail servers, name servers, and other DNS records.

A basic command follows this syntax:

$ nslookup domain-name

For example:

$ nslookup example.com

The output normally shows the DNS server that answered the request and the IP address associated with the domain.

Find the IP Address of a Domain

The most common use of nslookup is finding the IP address of a website.

$ nslookup google.com

A DNS response may contain an A record, which maps a domain name to an IPv4 address. An AAAA record performs a similar function for IPv6.

Query a Specific DNS Record

You can request a particular type of DNS record using the -type option.

$ nslookup -type=MX example.com

This command requests MX (Mail Exchange) records, which identify mail servers responsible for receiving email for the domain.

To find name servers:

$ nslookup -type=NS example.com

To query a TXT record:

$ nslookup -type=TXT example.com

Use a Specific DNS Server

Linux systems normally use DNS servers configured through the operating system. You can also ask a particular DNS server to perform the lookup.

$ nslookup example.com 8.8.8.8

Here, 8.8.8.8 is Google’s publicly available DNS resolver. This is useful when comparing responses from different DNS servers.

Reverse DNS Lookup

nslookup can also perform the reverse operation: finding a hostname associated with an IP address.

$ nslookup 8.8.8.8

This type of query is commonly called a reverse DNS lookup and relies on DNS records in the in-addr.arpa namespace for IPv4.

Interactive Mode

Running nslookup without arguments starts an interactive session.

$ nslookup

You can then enter a domain name or change the query type. For example:

> set type=MX
> example.com

Type exit to leave interactive mode.

Why is nslookup Useful?

Students and IT professionals can use nslookup to troubleshoot DNS problems, verify domain configuration, investigate email-related DNS records, check whether DNS changes have propagated, and compare results from different DNS servers. It is especially helpful when a website works by IP address but fails when accessed by its domain name.

The Linux nslookup command provides a simple way to investigate DNS resolution. By learning basic lookups, record-type queries, reverse lookups, and specific DNS-server queries, students gain a practical understanding of how DNS connects domain names with network services.

See Also:

dig Command

• https://www.testingdocs.com/linux-dig-command-with-examples/