postfix and ldap backend

[sin <sin@pvs.ro>]

Hi,

I have a problem using postfix with a ldap backend for relay purpouses:

My setup is something like this:
(Internet)-->(front-end postfix)--->(backend server and ldap server)

Right now, the relevant ldap settinggs from relay_recipient_maps
definition file are:

query_filter = (& (sAMAccountName=*)(mail=*)(proxyAddresses=smtp:%s))
result_attribute = proxyAddresses
result_format = smtp:%s

Everything is working fine except for one problem: I have no clue on how
to modify the query_filter in such a manner that will return no results
if some specified email addresses are matched, one for example would be
everyone@mycompany.tld

Based on what I have found on the Internet, i tried various queries,
some which looked like:

query_filter = (& sAMAccountName=*) (mail=*) (proxyAddresses=smtp:%s)
(!proxyAddresses=smtp:everyone@mycomapny.tld))

previously to this i tried something like:

relay_recipient_maps = hash:/etc/postfix/reject_users,
ldap:/etc/postfix/users1_ldap.cf, ldap:/etc/postfix/users2_ldap.cf

and in /etc/reject_users i put:

everyone@mycompany.tld	REJECT

but to no avail, postfix still relays mail to that address


Is there any way to solve my problem ?

additional data:
system is a sarge with postfix 2.1.5
ldap server is an ActiveDirectory



Thank you,

sin