To allow an application to notify network administrators that a SYN attack is taking place, the IP Helper API supports new SYN attack notification APIs named NotifySecurityHealthChange and CancelSecurityHealthChangeNotify. For information about these new APIs, see the Microsoft Developer Network (MSDN).
TCP/IP for Windows Server 2003 SP1 supports a new registry parameter that restricts the number of host routes that can be added to the local IP route table by receiving ICMP Redirect messages. The new registry parameter is HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services \Tcpip\Parameters\ MaxICMPHostRoutes (REG_DWORD type). MaxICMPHostRoutes has a default value of 1000. You should not change this value unless the computer needs to be able to add a large number of host routes by receiving ICMP Redirect messages.
The update to Windows Server 2003 SP1 available from Microsoft Knowledge Base article 898060 changes the default value of MaxICMPHostRoutes to 10000.