Active Directory is integrated with Domain Naming System (DNS) and requires it to be present to function. DNS is the naming system used for the Internet and on many Intranets. You can use DNS which is built into Windows 2000 and newer, or use a third party DNS infrastructure such as BIND if you have it in the environment. It is recommended you use Window’s DNS service as it is integrated into Windows and provides the easiest functionality.
AD uses DNS to name domains, computers, servers, and locate services.
A DNS server maps an object’s name to its IP address. For example, on the Internet, it is used to map a domain name (such as www.learnthat.com) to an IP address (such as 22.214.171.124). In an Active Directory network, it is used n
ot only to find domain names, but also objects and their IP address. It also uses service location records (SRV) to locate services.