When a connection is unexpected CUT - i.e. Ethernet cord pulled out of wall, modem unplugged, etc - it takes the OS up to several minutes to realize what has happened (and as a result, winsock does not know that the connection has been lost. Since winsock doesn't know, the component does not know either). Note that if you to send something on this connection - winsock will indeed realize that the connection has been broken and an exception will be thrown.