A. A. It doesn't. It never terminates a connection unless it is told to by a user, a KILL command is issued, or the operating system tells it that the network connection it is using has been disconnected.
How long the operating system takes to kill a network connection, or whether it is done at all, depends on the net-lib and network protocol used. For parameters on keep-alive frames and session time-outs for the relevant network protocol the best guide is the NT Server resource kit, which describes how NT's various networ layers work.
Typically, named-pipe connections over netbeui will be timed out quite quickly, followed by named-pipes over IP. If you're using tcp-ip sockets then these sessions aren't timed-out at all by default.