LDAP - List groups - php

Question

I need to list all groups within a certain group using PHP. This is what I have so far:
<?php
$ldap_dn = "ou=People,dc=something,dc=something,dc=something,dc=au";
$ldap_svr = "ldap.server.somewhere";
$ldap_domain = "domain.somewhere";
$conn=ldap_connect($ldap_svr) or die("Cannot connect to LDAP server!");
ldap_set_option ($conn, LDAP_OPT_REFERRALS, 0);
ldap_set_option($conn, LDAP_OPT_PROTOCOL_VERSION, 3);
ldap_bind($conn,"user#domain.somewhere","password");
$filter ="(ou=*)";
$justthese = array("ou");
$result=ldap_list($conn, $ldap_dn, $filter, $justthese) or die("No search data found.");
$info = ldap_get_entries($conn, $result);
for ($i=0; $i < $info["count"]; $i++) {
echo $info[$i]["ou"][0] . '<br />';
}
?>
This returns a list of groups, one of whch is 'Students', but I want to list all groups within 'Students'. How can I do this?
EDIT
Thanks to Fluffeh the Microsoft LDAP plugin allows me to search active directorys so I can tailor my PHP script accordingly, e.g. $ldap_dn = "ou=Units,ou=Groups,dc=somewhere,dc=somewher,dc=somewhere,dc=au";
So my mostly working code is:
<?php
$ldap_dn = "ou=Units,ou=Groups,dc=somewhere,dc=somewher,dc=somewhere,dc=au";
$ldap_svr = "ldap.server.somewhere";
$ldap_domain = "domain.somewhere";
$conn=ldap_connect($ldap_svr) or die("Cannot connect to LDAP server!");
ldap_set_option ($conn, LDAP_OPT_REFERRALS, 0);
ldap_set_option($conn, LDAP_OPT_PROTOCOL_VERSION, 3);
ldap_bind($conn,"user#domain.somewhere","password");
$filter ="(cn=*)";
$justthese = array('cn');
$result=ldap_list($conn, $ldap_dn, $filter, $justthese) or die("No search data found.");
$info = ldap_get_entries($conn, $result);
for ($i=0; $i < $info["count"]; $i++) {
echo $info[$i]["cn"][0] . '<br />';
}
?>

Answer 1

You need to actually pass the search to it. Currently you are using:
$filter ="(ou=*)";
This will need to change to contain 'Students'. While I am no LDAP expert, I would guess at the following:
$filter ="(cn=Students)";
Most of the LDAP stuff I have done has been sheer trial and error rather than knowing what I am doing, but this might put you on the right path.
There is also a Microsoft plugin - Active Directory Explorer you can use to at least browse the LDAP so that you know what to search for and under what branch.