LDAP is interesting, but not that easy to set up, at least not the server part.
I made different approaches to install OpenLDAP without success, the problem was always the schemas and initial data load.
With Red Hat Directory Server and its open source pendant CentOS Directory Server I was able to successfully install and maintain a LDAP directory.
Red Hat Directory Server is the successor of the Netscape Directory Server which has been purchased by Red Hat some time ago and has been open-sourced to comply with Red Hats product policy.
Is the Red Hat directory server a replacement for OpenLDAP? Yes and no. Yes because it is a open source product, available for free, and NO because there is only a small community around it.
To have a fully supported environment you need to buy a subscription from Red Hat. The starter is List-Priced @ 5000 USD/year for 500 entries. I think price tag is completely insane.
In contrary the open source variant CentOS directory server is for free. Decide by your self whats the right solution for you, OpenLDAP is definitively not ready for enterprise authentication.
Another approach is authenticating against a Microsoft Active Directory. This causes other problems which will be discussed in a future blog