Limited only by the resources of the computer, a virtual server can accept an unlimited number
of inbound connections. To prevent a server from becoming
overloaded, you can limit the number of connections made to the
POP3 resource. Once users are connected, you can also limit the
length of time idle connections remain logged on to the server.
By default, Exchange does not limit the number of incoming
connections and disconnects idle sessions after 10 minutes.