How DNS query works

When a DNS client needs to look up a name used in a program, it queries DNS servers to resolve the name.
Each query message the client sends contains three pieces of information, specifying a question for the server to answer:

1. A specified DNS domain name, stated as a fully qualified domain name (FQDN)
2. A specified query type, which can either specify a resource record by type or a specialized type of query operation
3. A specified class for the DNS domain name.
   

For Windows DNS servers, this should always be specified as the Internet (IN) class.