[Linux] Bash nslookup Uso: Query DNS records

Overview

The nslookup command is a network utility used to query Domain Name System (DNS) records. It allows users to obtain information about domain names, IP addresses, and other DNS-related data, making it a valuable tool for troubleshooting network issues and verifying DNS configurations.

Usage

The basic syntax of the nslookup command is as follows:

nslookup [options] [arguments]

Common Options

• -type=TYPE: Specifies the type of DNS record to query (e.g., A, AAAA, MX, TXT).
• -debug: Enables debugging mode to provide more detailed output.
• -timeout=SECONDS: Sets the time to wait for a response before timing out.
• -port=PORT: Specifies the port number to use for the DNS query (default is 53).

Common Examples

1. Querying an A record: To find the IP address associated with a domain name:

   nslookup example.com
   

2. Querying a specific DNS record type: To retrieve the MX (Mail Exchange) records for a domain:

   nslookup -type=MX example.com
   

3. Using a specific DNS server: To query a specific DNS server (e.g., Google’s public DNS):

   nslookup example.com 8.8.8.8
   

4. Debugging DNS queries: To enable debugging for more detailed output:

   nslookup -debug example.com
   

5. Querying a reverse DNS lookup: To find the domain name associated with an IP address:

   nslookup 93.184.216.34
   

Tips

• Always specify the type of record you are interested in to get more relevant results.
• Use the -debug option when troubleshooting to gain insights into the DNS resolution process.
• If you frequently query a specific DNS server, consider setting it as the default in your nslookup session for convenience.