Exception for localhost

It is possible to create users before or after access control is activated. MongoDB supports a localhost exception if you activate access control before establishing any user. This allows you to establish a user administrator in the admin database. Once a user has been created, you must log in as the user administrator to add other users as needed.

Authentication is enforced when access control is enabled on a MongoDB deployment, requiring users to identify themselves. Users can only conduct activities that are defined by their roles when visiting a MongoDB deployment with access control enabled.

The following tutorial utilizes the default authentication approach to provide access control on a solo mongo instance. See Authentication Techniques for a list of all supported authentication mechanisms.