Introduction

The nslookup command is a standard tool which is available on most operating systems, such as Linux, macOS, UNIX, and Windows.

To perform a single query, you can pass the name and nameserver on the command line.

EXAMPLE: nslookup www.cisco.com 129.118.1.47

Additional information

• Open your terminal or command app, such as Command Prompt in Windows, or Terminal in macOS.
• Type nslookup on a command line and press Enter/return.
• It will default to a nameserver, but you can change which nameserver you query against by typing server 129.118.1.46, for instance. From that point, you'll be querying against that nameserver (e.g., 129.118.1.46)
• To perform a query, just type the name at the prompt (e.g., www.cisco.com)
• By default, nslookup will only query for A and CNAME alias records, which are the most commonly accessed record types. If you want to do a comprehensive search, type set type=any, and nslookup will return any matching records, such as MX, NS, and SOA.
• Use your operating system's help documentation to review the various commands available within nslookup on your operating system.

EXAMPLE:

For MX (mail exchange) records in the DNS server:

C:\Users\jdoe>nslookup
Default Server:  netdnssoaac01.ttu.edu
Address:  129.118.1.46

> set type=mx
> ttu.edu
Server:  netdnssoaac01.ttu.edu
Address:  129.118.1.46

ttu.edu
        primary name server = netdcac01.ttu.edu
        responsible mail addr = noc.ttu.edu
        serial  = 1243965417
        refresh = 3600 (1 hour)
        retry   = 900 (15 mins)
        expire  = 3600000 (41 days 16 hours)
        default TTL = 3600 (1 hour)
>