After users log off the sessions are not always closing. Messages are being lost as they are sent to sessions that are no longer in use. Before restart off the server, one user had 5 sessions listed. Ghost session will be show in the list of session in the admin page but will be counted. If you get a user info from the client buddy list, it will list the ghost sessions attached to the user. A user logged on and off while another logged in use watched, user that logged was shown as still logged in.
Openfire - 3.9.3
I too am seeing this same hung session problem.
Not too long ago I upgraded to Openfire 3.9.3.
The server is running CentOS 5.10
Does anyone know why this problem reared its head with 3.9.3?
I’ve had an identical configuration for a few years since this server has been in production.
I’m going to give Wael’s suggestion to set idle time  .
Currently my xmpp.client.idle value is -1 (seemingly the default since I’ve documented my tweaks)
For now I’ve chosen 5 minutes (5601000 = 300000ms)
Most of my users are using Pidgin, so I’ll just have to trust it sends them out every 120 seconds since pings don’t appear  to be configurable.