Final answer:
To prevent users from reusing old passwords, you must configure the password history policy to define the number of unique new passwords required before an old one can be reused.
Step-by-step explanation:
To configure how many new passwords must be created before an old password can be reused, you must set the password history policy within your organization's security settings. This is often done in the security settings of a directory service such as Active Directory, where you can define a password policy that includes a setting for Enforce Password History.
This setting determines the number of unique new passwords a user must use before an old password can be reused. For instance, if you set this to 5, then a user would need to create five new passwords after their current one before they could reuse any of their previous passwords. It is recommended to use a high number for this setting to discourage password reuse and enhance security.