Computer Configuration\Windows Settings\Security Settings\Account Policies\Password Policy
Determines whether passwords must meet complexity requirements.
By default, this setting is disabled in the Default Domain Group Policy object (GPO) and in the local security policy of workstations and servers.
If this policy is enabled, then passwords must meet the minimum requirements described in the Notes section.
Notes
The default password filter (passfilt.dll) included with Windows 2000 requires that a password:
Complexity requirements are enforced upon password change or creation.
To create custom password filters, refer to the Microsoft Platform Software Development Kit and the Microsoft Knowledge Base.