Centerelaized email address book for sendmail+dovecot
I am using Centos 5.2 + sendmail+dovecot as my mail server and working fine with 150 users. I need to implement centralized email address book for the above system as same like windows Active directory environment as per the most of client request. Clients are using Outlook Express and few MS Outlook too. Centralized address book can be accessed from the Outlook Express and MS Outlook.
How can I config this in my existing environment?. Is there any good simple reference.