OpenLDAP is a freely available LDAP sever and client API. It is licensed under terms similar to the standard BSD license. The current version of OpenLDAP (2001) is 2.0. Some features planned for 2.1 are an LDAP C++ API and SASL authentication/authorization mapping. The OpenLDAP Project has a web site at http://www.openldap.org, whre they state their goals as:
The OpenLDAP Project is a collaborative effort to develop a robust, commercial-grade, fully featured, and open source LDAP suite of applications and development tools.

OpenLDAP is derived from University of Michigan LDAP version 3.3. The University of Michigan's LDAP server is not longer actively developed. OpenLDAP has the following enhancements over UofM LDAP:

  • LDAPv3 protocol support
  • Better security features
  • Support for additional backend databases
  • Bug fixes