!!! Overview[1]
[{$pagename}] provide a way for you to implement [Password Policy] and [Password Modify Operation] [notification]. 


[Passfilt.dll] is Microsoft's implementation of a password filter.

When a [Password Modify Operation] is made, the [Local Security Authority] ([LSA]) calls the [{$pagename}] registered on the system. Each [{$pagename}] is called twice: 
* first to validate the new [password] 
* and then, after all filters have validated the new [password], to notify the [{$pagename}] that the change has been made. 

[{Image src='Active Directory and Passwords/LSA-Password-Filter.png' caption='Password change request' style='font-size: 120%; color: green;'}]

Password change notification can be used to synchronize password changes to foreign [Credential] [Data Stores].

[{$pagename}] are used to enforce [Password Policy]. Filters validate new passwords and indicate whether the new password conforms to the implemented password policy.
* For an overview of using password filters, see [Using Password Filters.|http://msdn.microsoft.com/en-us/library/ms722496(v=VS.85).aspx|target='_blank']
* For a list of password filter functions, see [Password Filter Functions.|http://msdn.microsoft.com/en-us/library/ms721849(v=VS.85).aspx#password_filter_functions|target='_blank']

The following topics provide more information about password filters:
* [Password Filter Programming Considerations|http://msdn.microsoft.com/en-us/library/ms721884(v=VS.85).aspx|target='_blank']
* Strong Password Enforcement and [Passfilt.dll]

!! More Information
There might be more information for this subject on one of the following:
[{ReferringPagesPlugin before='*' after='\n' }]
----
* [#1] - [Password Filters|http://msdn.microsoft.com/en-us/library/ms721882(VS.85).aspx|target='_blank'] - based on information obtained 2016-01-02- 
* [#2] - [Password Filter Programming Considerations|https://docs.microsoft.com/en-us/windows/win32/secmgmt/password-filter-programming-considerations|target='_blank'] - based on information obtained 2020-02-11 
* [#3] - [Installing and Registering a Password Filter DLL|https://docs.microsoft.com/en-us/windows/win32/secmgmt/installing-and-registering-a-password-filter-dll|target='_blank'] - based on information obtained 2020-02-11