Password Complexity in Linux

[Scott Ruckh]

Hi All

I would like to setup passwd complexity on our Linux servers .

Min 8 characters - 1 upper , 1 digit and 1 Lower character

Last used 4 passwords should not be used

And also i want to set Passwd expiry for user accounts which are already 
created and These passwd complexity should apply to users which has alreay 
been created .

I Need your valuable help and advice

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man pam_cracklib