Querying DNS with dig Command in Linux - Details with Commands

 What is dig Command in Linux ?

    The dig command in Linux is a utility used for querying DNS (Domain Name System) servers. It is primarily used to obtain DNS-related information such as domain name resolution, IP addresses, and other DNS records.

    The dig command can be used to perform various DNS queries, such as:

1. A simple A record query to retrieve the IP address of a domain:

   css
   dig example.com A
   

2. A reverse DNS lookup to obtain the hostname associated with an IP address:

   dig -x 192.0.2.1
   

3. A query to obtain the DNS server responsible for a domain:

   dig example.com NS
   

4. A query to obtain the start of authority (SOA) record for a domain:

   dig example.com SOA
   

5. A query to obtain a specific type of DNS record, such as a TXT record:

   dig example.com TXT
   

    The dig command can also be used with various options and flags to customize the output and behavior of the query. For example, the +short option can be used to display only the IP address or domain name without additional information.

    dig is usually included in the dnsutils package on most Linux distributions. To install dig, you can follow these steps:

1. Open a terminal window on your Linux system.

2. Update the package lists:

   sql
   sudo apt-get update
   

   If you are using a different package manager, replace apt-get with the appropriate command.

3. Install the dnsutils package:

   arduino
   sudo apt-get install dnsutils
   

   This command will install dig along with other DNS-related utilities included in the dnsutils package.

4. Verify the installation:

   dig example.com
   

   This command will perform a DNS lookup for the example.com domain using dig. If dig is installed correctly, it should display the IP address associated with the domain.

    If you need to perform a large number of dig queries, you can automate the process using a batch script. Here is an example of how to perform batch processing of dig queries in Linux:

1. Create a text file containing the list of domain names to query, one per line. For example, create a file called domains.txt and add the following lines:

   example.com
   google.com
   yahoo.com
   

2. Create a bash script file to perform the dig queries. For example, create a file called batch_dig.sh and add the following lines:

   bash
   #!/bin/bash
   
   while read domain; do
       echo "Querying $domain..."
       dig $domain +short
   done < domains.txt
   

   This script will read each line of the domains.txt file and use dig to perform a query for each domain name. The +short option is used to display only the IP address without additional information.

3. Make the script executable:

   bash
   chmod +x batch_dig.sh
   

4. Run the script:

   bash
   ./batch_dig.sh
   

   This will execute the script and perform a dig query for each domain name in the domains.txt file. The output will be displayed on the terminal window.