[CentOS] Every user in LDAP queried when one user logs on.

Hi 
I have configured a machine to authenticate against LDAP.  When I log onto the box using the newly created user I see a LDAP search request for every user that exist in the directory. If I have only 20 users even a 100 that is not a problem but when I start going to 10000 users I start getting some weird errors and timeouts because of the time it takes to download the data to the client.

I have tested this against 389 Directory Server and OpenLDAP and both give the same behaviour described above.

I have tried adding a nss_base directives in /etc/ldap.conf but it has had no effect. 

my /etc/ldap.conf:


binddn          uid=SysAuth,ou=Service Accounts,dc=mycompany
bindpw          secret
pam_password clear
base            dc=betfair
nss_base_passwd         ou=people,dc=mycompany?sub
nss_base_group          ou=Groups,dc=mycompany?sub
nss_base_group          ou=PrivateGroups,dc=mycompany?sub
nss_base_group          ou=SystemGroups,dc=mycompany?sub

sizelimit                       1000
idle_timelimit                  5
timelimit                       10
bind_timelimit                  5
nss_reconnect_tries             1
nss_reconnect_maxconntries      1
nss_reconnect_sleeptime         1
nss_reconnect_maxsleeptime      1
nss_reconnect_maxconntries      1

I have also played around with various debug levels in /etc/ldap.conf but I have not really been succesfull in matching requests I see there to requests I see in wireshark. The man page in centos (man pam_ldap and nss_ldap ) also does not make any mention of available log levels or what they do. I have also scanned the source code for some more info on log levels but did not find anything usefull. If it is in the source code then please point me to it.

I have gone through the pam list logs and the closest I could find was the following thread:
https://www.redhat.com/archives/pam-list/2009-September/thread.html and a similar thread in December 2010.  This threads although similar is related to groups and my problem is with every user being queried.

I am fairly certain (hopeful at least) that is a config error on my part but I have not been able to find that error yet and would welcome any assistance in finding the problem.

My system-auth in /etc/pam.d/ looks as follows:

auth        required      pam_env.so
auth        sufficient    pam_unix.so nullok try_first_pass
auth        requisite     pam_succeed_if.so uid >= 500 quiet
auth        sufficient    pam_ldap.so  use_first_pass
auth        required      pam_deny.so

account     required      pam_access.so
account     required      pam_unix.so broken_shadow
account     sufficient    pam_localuser.so
account     sufficient    pam_succeed_if.so uid < 500 quiet
account     [default=bad success=ok user_unknown=ignore] pam_ldap.so debug
account     required      pam_permit.so

password    requisite     pam_cracklib.so try_first_pass retry=3
password    sufficient    pam_unix.so nullok try_first_pass use_authtok
password    sufficient    pam_ldap.so use_authtok
password    required      pam_deny.so

session     optional      pam_keyinit.so revoke
session     required      pam_limits.so
session     optional      pam_mkhomedir.so
session     [success=1 default=ignore] pam_succeed_if.so service in crond quiet use_uid
session     required      pam_unix.so
session     optional      pam_ldap.so

Using CentOS release 5.4 on the client and 5.5 on the server but I see the same result if the server is on 5.4.

Regards

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