>did any one experience to installed LDAP as global address book server? Yes. >please give me some guidelines... If you have OpenLDAP 2.1.x http://www.openldap.org/doc/admin21/ If you have OpenLDAP 2.0.x http://www.openldap.org/doc/admin20/ and/or ftp://ftp.kalamazoolinux.org/pub/pdf/ldapv3.pdf If you might need to work with M$ apps take a look at http://www.openldap.org/faq/data/cache/295.html