vim /etc/login.defs

PASS_MAX_DAYS 90
 PASS_MIN_DAYS 1 
 PASS_MIN_LEN 8  
 PASS_WARN_AGE 7 
 FAIL_DELAY 10 
 FAILLOG_ENAB yes 
 SYSLOG_SU_ENAB yes 
 SYSLOG_SG_ENAB yes 
 MD5_CRYPT_ENAB yes