HOWTO : OpenLDAP 2.4 Replication on CentOS 6.2

We continue our OpenLDAP 2.4 on CentOS 6.2 with a description on how to setup  between two OpenLDAP 2.4 servers. This happens to be the final bullet point in our list of goals :

1. Install OpenLDAP 2.4.
2. Configure Transport Layer Security (TLS).
3. Manage users and groups in OpenLDAP.
4. Configure pam_ldap to authenticate users via OpenLDAP.
5. Use OpenLDAP as sudo's configuration repository.
6. Use OpenLDAP as automount map repository for autofs.
7. Use OpenLDAP as NFS netgroup repository again for autofs.
8. Use OpenLDAP as the Kerberos principal repository.
9. Setup OpenLDAP backup and recovery.
10. Setup OpenLDAP replication.

Of course the first thing to do in order to be able to replication our DIT is to have another CentOS machine. So go ahead and install it on a seperate computer. We will continue with our example two machines : alice and bob. Alice is the current OpenLDAP server while bob was the client. At the end of this document, bob will be the second OpenLDAP server. Which in OpenLDAP syncrepl parlance, we have these entities :

• provider : alice.company.com (a.k.a. master server)
• consumer : bob.company.com (a.k.a. replica server)