[Linux] Bash dig Uso: DNS lookup tool

Overview

The dig command, short for “Domain Information Groper,” is a powerful tool used for querying DNS (Domain Name System) records. It allows users to retrieve various types of DNS information, including A records, MX records, and more, making it essential for network troubleshooting and domain management.

Usage

The basic syntax of the dig command is as follows:

dig [options] [arguments]

Common Options

• @server: Specify a DNS server to query (e.g., @8.8.8.8 for Google DNS).
• -t type: Specify the type of DNS record to query (e.g., A, MX, TXT).
• +short: Display a simplified output with only the answer.
• +trace: Follow the delegation path from the root DNS servers to the queried domain.

Common Examples

Here are some practical examples of using the dig command:

1. Querying an A Record:

   dig example.com
   

2. Querying an MX Record:

   dig -t MX example.com
   

3. Using a Specific DNS Server:

   dig @8.8.8.8 example.com
   

4. Getting a Short Answer:

   dig +short example.com
   

5. Tracing the DNS Resolution Path:

   dig +trace example.com
   

Tips

• Use the +short option for quick lookups when you only need the answer without additional details.
• When troubleshooting DNS issues, the +trace option can help identify where the resolution is failing.
• Always specify a DNS server if you suspect issues with your local resolver to get a different perspective on the DNS records.