389-ds-base 1.2.10.4-0ubuntu3 (amd64 binary) in ubuntu precise

 The 389 Directory Server is a robust, scalable open-source server
 designed to manage large directories of users and resources. It is based
 on an open-systems server protocol called the Lightweight Directory
 Access Protocol (LDAP).
 .
 Amongst other features, it supports 4-Way multi-master replication,
 Active Directory user and group synchronization, great scalability and
 on-line, zero downtime, LDAP-based update of schema, configuration,
 management and in-tree Access Control Information (ACIs).