Pls help : how to make mail id as unique attribute

[Somnath Pal <pal@unicc.org>]

Hi list,

We have an openldap server 2.4 on redhat
enterprise linux 4 update 7. We import users from Windows Active Directory(AD)
running Windows Server 2003. 

We are mapping the mail attribute from
the source (AD) to the destination (openldap) & want the mail id to
be unique accross the ldap directory so that no two email ids will be same
while replicating from different Source . 

How to achive that ? Do we have to modify
our schema ? 

We are using the following schema in
our slapd.conf -

include        
/opt/openldap/etc/openldap/schema/core.schema
include        
/opt/openldap/etc/openldap/schema/cosine.schema
include        
/opt/openldap/etc/openldap/schema/inetorgperson.schema


Can you pls help ?

Thanks & Regards,

Somnath Pal
Server Management Unit
International Computing Centre (ICC)
E-mail: pal@unicc.org