The following is a list of black hole router detection changes that are included in Windows Server 2003 SP2:
• By default, black hole detection is turned on.
• Black hole probing is performed only for connections in established or advanced states.
• Black hole probing is performed only for connections on which there is no full-size segment acknowledgement.
• If black hole probing fails, the TCP Maximum Segment Size (MSS) of the connection is restored to what it used to be before probing.
• With black hole router detection turned off in versions of Windows that are earlier than Windows Server 2003 SP2, a connection times out approximately after 63 * RTT. In Windows Server 2003 SP2, connections time out after 71 * RTT.