A domain is defined as a collection of users, computers, database servers, etc that are grouped together for some common purpose.
The database of these shared groups and resources is stored on one or more computers known as domain controllers.
It is a server that manages these groups that work together on the same network.
It is also responsible for administrating security and managing permissions in order to control access to the resources which are shared between multiple computers and users in one or more domains.
These permissions involve user authentication and authorization. Domain controllers is used to acknowledge authentication requests of users by verifying their username and password.
Domain controllers simplify security management in larger networks.
However domain controller serves need more hardware and resources for the purpose of securing shared information.
