The Linux dig command allows you to query DNS servers and perform DNS lookups. You can also find the domain an IP address leads back to. We’ll show you how!
People use the Linux dig command to query Domain Name System (DNS) servers. dig is an acronym for Domain Information Groper. With dig, you can query DNS servers for information regarding various DNS records, including host addresses, mail exchanges, name servers, and related information. It was intended to be a tool for diagnosing DNS issues. However, you can use it to poke around and learn more about DNS, which is one of the central systems that keep the internet routing traffic.
[Source: How-To Geek]