control ftp login in openldap

[hangyu]

In the config file /etc/ldap.conf of RH server, I have add "pam_check_host_attr yes", so that the user login is controlled by the user attribute , ( eg. host: ova_server ) , now the user can access the ova_server by telnet , ssh , however , if I want to control the ftp login , only a list of specific users ( eg. only three system administrators ) can ftp login to the server , can advise what can I do ? thx