PHP LDAP returning partial data
<p>I am accessing an Active Directory server via PHP's ldap_* functions.  Part of the task is to determine application permissions based on AD group membership.  For my user this works correctly, for some other users, the "memberOf" field is not part of the returned data.  What would cause this attribute to be missing?  What can I do to determine group membership in its absence?</p>

<pre><code>$ds = ldap_connect($ldap['host']);
ldap_set_option($ds, LDAP_OPT_PROTOCOL_VERSION, 3);
ldap_set_option($ds, LDAP_OPT_REFERRALS, 0);
if ($ds) {
    $r  = ldap_bind($ds, $ldap['user'], $ldap['pass']);
    $sr = ldap_search($ds, $ldap['path'], "samaccountname=".$username, array(), 0, 1000, 5);
    $info = ldap_get_entries($ds, $sr);
}
</code></pre>