I have installed openldap 2.4.23 on CentOS 6.3 using the yum package 'openldap-servers'.
When I follow instructions to configure openldap for SSL (such as http://www.overclockers.com/forums/showthread.php?t=707070 or http://itdavid.blogspot.ca/2012/05/howto-centos-6.html), everything seems good when I bounce LDAP- the port is open, so it appears the server is listening.
However, when I attempt to connect via LDAPS, the client and server hang. Connecting via openssl_client gives the same behaviour (it displays CONNECTED and then hangs). Nothing appears in the system log or openldap logs.
(Note: I figured it out and want to save anyone else the aggravation- just posting it as a question in order to follow ServerFault posting guidelines).