We are using Centos 6 on SE Linux and we are trying to get the failed logins to lock the accounts.

In the past I have been required to configure our Linux Red Hat 5 systems so when users enter the wrong password 3 consecutive times the account is locked, and resets in 15 minutes. I have also had to used complex passwords (Upper Case, Lower Case, Special Character, and Digit). Using all that I know from Red Hat I just can't quite figure out what I'm doing wrong on the system-auth file and /etc/login.defs file. Can anyone provide me an example (or a website) that has a known good configuration I can view and add to my system?