Set Linux Password Policy

/Etc/login. defs
PASS_MAX_DAYS 99999 # Maximum Password validity period, 99999: Permanent
PASS_MIN_DAYS 0 # indicates whether the password can be changed. If the password is set to 0, the password can be changed. If the password is set to not 0, the password can be changed.
PASS_MIN_LEN 5 # minimum password length. This parameter is no longer valid when pam_cracklib module is used.
PASS_WARN_AGE 7 # How many days before the password expires when the user logs on to notify the user to change the password
/Etc/pam. d/system-auth
Password requisite/lib/security/$ ISA/pam_cracklib.so retry = 3
Password sufficient/lib/security/$ ISA/pam_unix.so nullok use_authtok md5 shadow use_first_pass
Password required/lib/security/$ ISA/pam_deny.so
Change
Password required pam_passwdqc.so min = disabled, disabled, 12, 8, 7 max = 40 passphrase = 3 match = 4 similar = deny random = 42 enforce = everyone retry = 3
# Password requisite/lib/security/$ ISA/pam_cracklib.so retry = 3
Password sufficient pam_unix.so nullok use_authtok md5 shadow use_first_pass
Password required/lib/security/$ ISA/pam_deny.so