Changes made to the password length properties take effect immediately, but apply only to new user accounts or new passwords. For example, if you change the minimum password length from eight characters to ten, all new users must have a password that is a minimum of ten characters long. However, existing users will still be able to use their eight character passwords.
Changes made to the expiration time limit take effect after the appropriate time interval. For example, if you change the password expiration time limit to thirty days, user accounts get suspended if their passwords have not been changed before the time expires. Users will be prompted to change their passwords two weeks before the suspension takes place. By default, the strong password option is turned off. When this feature is turned on, as users change their passwords, they must provide strong passwords. Until such a change is made, their old “weak” passwords continue to work.
Selecting this check box also changes the value in the Minimum password length field to 3. You can increase it if you choose.