Authconfig

Authconfig can help you in setting up configuration for access

/etc/sysconfig/authconfig
Used to track whether or not particular authentication
mechanisms are enabled. Currently includes variables
named USESHADOW, USEMD5, USEKERBEROS, USELDAPAUTH, USESM-
BAUTH, USEHESIOD, USENIS, USELDAP.
/etc/passwd,
Used for shadow password support.
/etc/yp.conf
Configuration file for NIS support.
/etc/sysconfig/network
Another configuration file for NIS support.
/etc/ldap.conf
/etc/openldap/ldap.conf Used to configure LDAP (and
OpenLDAP, respectively).
/etc/krb5.conf
Used to configure Kerberos 5.
/etc/krb.conf
Used to configure Kerberos IV (write-only).
/etc/hesiod.conf
Used to configure Hesiod.
/etc/pam_smb.conf
Used to configure SMB authentication.

/etc/nsswitch.conf
Used to configure user information services.
/etc/pam.d/system-auth
Used to configure PAM for system services via
pam_stack(8).