Password must meet complexity requirements Description
This security setting determines whether passwords must meet complexity requirements.
 
If this policy is enabled, passwords must meet the following minimum requirements:
 
Not contain all or part of the user's account name  
Be at least six characters in length  
Contain characters from three of the following four categories:  
English uppercase characters (A through Z)  
English lowercase characters (a through z)  
Base 10 digits (0 through 9)  
Non-alphabetic characters (for example, !, $, #, %)  
Complexity requirements are enforced when passwords are changed or created.
 
To create custom password filters, see the Microsoft Platform Software Development Kit and TechNet on the Microsoft Web site.(http://www.microsoft.com/)
 
Default:  
 
Enabled on domain controllers.  
Disabled on stand-alone servers.  
 Note
 
By default, member computers follow the configuration of their domain controllers.  
Configuring this security setting
You can configure this security setting by opening the appropriate policy and expanding the console tree as such: Computer Configuration\Windows Settings\Security Settings\Account Policies\Password Policy\
 
For specific instructions about how to configure password policy settings, see To apply or modify password policy.
 
For more information, see:
 
Strong Passwords  
Best practices for passwords  
Password policy  
Security Configuration Manager Tools