Ldap Authentication在php中检索不到任何信息

Question

我已经成功验证了php中的ldap，但我无法在搜索过程中检索信息。此广告身份验证在.net应用程序中工作正常但在php中我在搜索期间未收到任何信息。

    $search_filter = "(sAMAccountName=*xyz*)" ; 
    $attributes = array("memberof","givenname");
    $ldap = ldap_connect($server);

    if($ldap) 
        echo "successful";  

    ldap_set_option($ldap, LDAP_OPT_PROTOCOL_VERSION, 3); // generally needed with AD.
    //ldap_set_option($ldap, LDAP_OPT_PROTOCOL_VERSION, 2.4);
    ldap_set_option($ldap, LDAP_OPT_REFERRALS, 0);

    $ldapbind  = ldap_bind($ldap,$username,$password); 

    if ($ldapbind) {
        echo "<br> LDAP Connect successful...";
    } else {
        echo "<br>LDAP Connect failed...";      
    }

    $search = ldap_search($ldap, $base_dn, $search_filter);
    $data = ldap_get_entries($ldap, $search);