With this tool, you will be able to see all the important DNS Records a website has. It will retrieve all MX Records, A Records, NS Records, and TXT Records. With this information, you will be able to see where the DNS Records are pointing too. You might also be able to determine where the website is hosted.
MX Records are mainly used for email servers. They tell the internet where all the mail should be sent to or a specific domain name. You might see more than one MX Record for a domain if they are using a hosted mail server.
A Records are used to point clients to a specific server when requesting the website. It will point all website traffic to those IP Addresses list for those A Records.
NS Records are used for letting you know what DNS servers are being used and their IP Addresses. You will see multiple servers listed on this section.
TXT Records are used for a number of things. They are used to store records for other servers to read. They can store SPF Records, which are used to identify your identity for emails. They are also store verification information for services like google.com webmaster tools or ssl domain verification code.