The ReservedPort property determines if a reserved local
port number is used by the control when the socket is created
(reserved port numbers are in the range of 513 through 1023,
inclusive). Some application protocols require that the client bind
to a local port number in this range. By setting the LocalPort
property to 0 and the ReservedPort property to True, a
reserved port number will be used when the socket is created. The
default value for this property is False, which specifies that a
standard port number with a value of 1024 or higher will be bound to
the socket unless the LocalPort property is explicitly set to
a non-zero value. Reserved ports should only be used by those
applications that expressly need them to implement a specific
protocol.
It is possible that the error swErrorAddressInUse will be
returned when attempting to connect using a reserved port number. The
value of the LocalPort property will contain the reserved port
number that could not be used.