I ran into issues hitting the max filedescriptors setting and found that it was because the server never terminates idle connections.  I have an idle timeout setting of 1200 seconds (20min).  If I make an LDAP request from a client to the directory server, the tcp connection stays in ESTABLISHED state on the server side forever.  I ran tcpdump on the client side and not a single packet of traffic was sent to the server during for hours. 

Any idea why this connection would not be terminated after 1200 sec?