Specifies when the IMAP server drops idle IMAP client sessions. We
recommend specifying a
setting greater than ten minutes; many IMAP clients poll for new mail
every ten minutes and
the overhead of supporting idle session is less than the overhead
required to support clients
logging on and opening mailboxes.
There is no default setting; although without this setting, the server
drops idle sessions
after 30 minutes.
IMAP_Session_Timeout = number of minutes